GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2025-21791 (GCVE-0-2025-21791)

Vulnerability from cvelistv5 – Published: 2025-02-27 02:18 – Updated: 2026-08-05 11:54
VLAI
Title
vrf: use RCU protection in l3mdev_l3_out()
Summary
In the Linux kernel, the following vulnerability has been resolved: vrf: use RCU protection in l3mdev_l3_out() l3mdev_l3_out() can be called without RCU being held: raw_sendmsg() ip_push_pending_frames() ip_send_skb() ip_local_out() __ip_local_out() l3mdev_ip_out() Add rcu_read_lock() / rcu_read_unlock() pair to avoid a potential UAF.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-02-27 17:57 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < 6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e (git)
Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < 20a3489b396764cc9376e32a9172bee26a89dc3b (git)
Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < 5bb4228c32261d06e4fbece37ec3828bcc005b6b (git)
Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < c7574740be8ce68a57d0aece24987b9be2114c3c (git)
Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < c40cb5c03e37552d6eff963187109e2c3f78ef6f (git)
Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < 022cac1c693add610ae76ede03adf4d9d5a2cf21 (git)
Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < 7b81425b517accefd46bee854d94954f5c57e019 (git)
Affected: a8e3e1a9f02094145580ea7920c6a1d9aabd5539 , < 6d0ce46a93135d96b7fa075a94a88fe0da8e8773 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.9
Unaffected: 0 , < 4.9 (semver)
Unaffected: 5.4.291 , ≤ 5.4.* (semver)
Unaffected: 5.10.235 , ≤ 5.10.* (semver)
Unaffected: 5.15.179 , ≤ 5.15.* (semver)
Unaffected: 6.1.129 , ≤ 6.1.* (semver)
Unaffected: 6.6.79 , ≤ 6.6.* (semver)
Unaffected: 6.12.16 , ≤ 6.12.* (semver)
Unaffected: 6.13.4 , ≤ 6.13.* (semver)
Unaffected: 6.14 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2025-21791",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-02-27T17:57:16.236835Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-416",
                "description": "CWE-416 Use After Free",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-02-27T18:02:26.723Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T20:59:34.647Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/l3mdev.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            },
            {
              "lessThan": "20a3489b396764cc9376e32a9172bee26a89dc3b",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            },
            {
              "lessThan": "5bb4228c32261d06e4fbece37ec3828bcc005b6b",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            },
            {
              "lessThan": "c7574740be8ce68a57d0aece24987b9be2114c3c",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            },
            {
              "lessThan": "c40cb5c03e37552d6eff963187109e2c3f78ef6f",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            },
            {
              "lessThan": "022cac1c693add610ae76ede03adf4d9d5a2cf21",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            },
            {
              "lessThan": "7b81425b517accefd46bee854d94954f5c57e019",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            },
            {
              "lessThan": "6d0ce46a93135d96b7fa075a94a88fe0da8e8773",
              "status": "affected",
              "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/net/l3mdev.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.9"
            },
            {
              "lessThan": "4.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.291",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.235",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.179",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.129",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.79",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.13.*",
              "status": "unaffected",
              "version": "6.13.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.291",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.235",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.179",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.129",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.79",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.16",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.13.4",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.14",
                  "versionStartIncluding": "4.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvrf: use RCU protection in l3mdev_l3_out()\n\nl3mdev_l3_out() can be called without RCU being held:\n\nraw_sendmsg()\n ip_push_pending_frames()\n  ip_send_skb()\n   ip_local_out()\n    __ip_local_out()\n     l3mdev_ip_out()\n\nAdd rcu_read_lock() / rcu_read_unlock() pair to avoid\na potential UAF."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Both halves of the race are driven from the local system \u2014 a `sendmsg()` on a local socket for the read side, and RTNL link operations (VRF delete/unenslave) for the free side. A remote peer cannot induce the VRF teardown that arms the use-after-free.\nAC:L - The attacker controls both sides of the race and can loop them indefinitely: one thread sends UDP/raw packets out a VRF-enslaved device while another repeatedly unenslaves/deletes the VRF master, with preemption pressure raised at will. `do_vrf_del_slave()` widens the window further by unlinking the adjacency before clearing `IFF_L3MDEV_SLAVE`.\nPR:L - The transmit side needs no privileges at all (ordinary UDP sendmsg), and the VRF create/enslave/delete side needs only CAP_NET_ADMIN within a network namespace, which an unprivileged user obtains via `unshare -Urn`.\nUI:N - The attacker\u0027s own threads perform every step \u2014 socket sends and netlink link operations \u2014 with no victim action required.\nS:U - The use-after-free and its consequences are confined to the kernel\u0027s own security authority; no VM, IOMMU, or other trust boundary is crossed.\nC:H - The freed `netdev_adjacent` sits in a general kmalloc cache and is readily groomed, letting the attacker supply `upper-\u003edev`, after which `master-\u003el3mdev_ops` and `-\u003el3mdev_l3_out` are read from an attacker-chosen address \u2014 an arbitrary kernel read primitive.\nI:H - The same reclaimed object yields an indirect call through an attacker-controlled function pointer with `master` as the first argument, giving control-flow hijack and thus arbitrary kernel-state modification.\nA:H - Even unweaponized, dereferencing a stale adjacency entry and calling through garbage function pointers reliably oopses or panics the kernel, and the attacker can retrigger it at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:54:28.163Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e"
        },
        {
          "url": "https://git.kernel.org/stable/c/20a3489b396764cc9376e32a9172bee26a89dc3b"
        },
        {
          "url": "https://git.kernel.org/stable/c/5bb4228c32261d06e4fbece37ec3828bcc005b6b"
        },
        {
          "url": "https://git.kernel.org/stable/c/c7574740be8ce68a57d0aece24987b9be2114c3c"
        },
        {
          "url": "https://git.kernel.org/stable/c/c40cb5c03e37552d6eff963187109e2c3f78ef6f"
        },
        {
          "url": "https://git.kernel.org/stable/c/022cac1c693add610ae76ede03adf4d9d5a2cf21"
        },
        {
          "url": "https://git.kernel.org/stable/c/7b81425b517accefd46bee854d94954f5c57e019"
        },
        {
          "url": "https://git.kernel.org/stable/c/6d0ce46a93135d96b7fa075a94a88fe0da8e8773"
        }
      ],
      "title": "vrf: use RCU protection in l3mdev_l3_out()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-21791",
    "datePublished": "2025-02-27T02:18:29.014Z",
    "dateReserved": "2024-12-29T08:45:45.766Z",
    "dateUpdated": "2026-08-05T11:54:28.163Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-21791",
      "date": "2026-09-18",
      "epss": "0.00263",
      "percentile": "0.18522"
    },
    "microsoft_vex": {
      "current_release_date": "2026-02-18T02:19:19.000Z",
      "cve": "CVE-2025-21791",
      "id": "msrc_CVE-2025-21791",
      "initial_release_date": "2025-02-02T00:00:00.000Z",
      "product_status:fixed": "5",
      "product_status:known_affected": "5",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "vrf: use RCU protection in l3mdev_l3_out()",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-21791.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "include/net/l3mdev.h"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "20a3489b396764cc9376e32a9172bee26a89dc3b",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5bb4228c32261d06e4fbece37ec3828bcc005b6b",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c7574740be8ce68a57d0aece24987b9be2114c3c",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c40cb5c03e37552d6eff963187109e2c3f78ef6f",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "022cac1c693add610ae76ede03adf4d9d5a2cf21",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "7b81425b517accefd46bee854d94954f5c57e019",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6d0ce46a93135d96b7fa075a94a88fe0da8e8773",
                    "status": "affected",
                    "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "include/net/l3mdev.h"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "4.9"
                  },
                  {
                    "lessThan": "4.9",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.4.*",
                    "status": "unaffected",
                    "version": "5.4.291",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.10.*",
                    "status": "unaffected",
                    "version": "5.10.235",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.179",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.129",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.79",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.16",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.13.*",
                    "status": "unaffected",
                    "version": "6.13.4",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.14",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "E1C17A14-0DFF-4500-8A61-0B4CE1F404E5",
                    "versionEndExcluding": "6.1.129",
                    "versionStartIncluding": "4.9",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "B16AADE5-B2FD-4C14-B4E4-85E8EDAFE775",
                    "versionEndExcluding": "6.6.79",
                    "versionStartIncluding": "6.2",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "13C8DB18-FC60-425F-84E5-3EDDEC61B2FC",
                    "versionEndExcluding": "6.12.16",
                    "versionStartIncluding": "6.7",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "2A2093ED-74A9-43F9-AC72-50030F374EA4",
                    "versionEndExcluding": "6.13.4",
                    "versionStartIncluding": "6.13",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "186716B6-2B66-4BD0-852E-D48E71C0C85F",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "0D3E781C-403A-498F-9DA9-ECEE50F41E75",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvrf: use RCU protection in l3mdev_l3_out()\n\nl3mdev_l3_out() can be called without RCU being held:\n\nraw_sendmsg()\n ip_push_pending_frames()\n  ip_send_skb()\n   ip_local_out()\n    __ip_local_out()\n     l3mdev_ip_out()\n\nAdd rcu_read_lock() / rcu_read_unlock() pair to avoid\na potential UAF."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: vrf: usar protecci\u00f3n RCU en l3mdev_l3_out() l3mdev_l3_out() se puede llamar sin que se retenga RCU: raw_sendmsg() ip_push_pending_frames() ip_send_skb() ip_local_out() __ip_local_out() l3mdev_ip_out() Agregue el par rcu_read_lock() / rcu_read_unlock() para evitar un posible UAF."
          }
        ],
        "id": "CVE-2025-21791",
        "lastModified": "2026-06-17T08:44:17.250",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "nvd@nist.gov",
              "type": "Primary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2025-21791",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-02-27T17:57:16.236835Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2025-02-27T03:15:19.970",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/022cac1c693add610ae76ede03adf4d9d5a2cf21"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/20a3489b396764cc9376e32a9172bee26a89dc3b"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/5bb4228c32261d06e4fbece37ec3828bcc005b6b"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/6d0ce46a93135d96b7fa075a94a88fe0da8e8773"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/7b81425b517accefd46bee854d94954f5c57e019"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/c40cb5c03e37552d6eff963187109e2c3f78ef6f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/c7574740be8ce68a57d0aece24987b9be2114c3c"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-416"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          },
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-416"
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T19:21:52+00:00",
      "cve": "CVE-2025-21791",
      "id": "CVE-2025-21791",
      "initial_release_date": "2025-02-27T00:00:00+00:00",
      "product_status:fixed": "917",
      "product_status:known_affected": "112",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vrf: use RCU protection in l3mdev_l3_out()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-21791.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2025-11-03T20:59:34.647Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
              },
              {
                "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "attackComplexity": "LOW",
                  "attackVector": "LOCAL",
                  "availabilityImpact": "HIGH",
                  "baseScore": 7.8,
                  "baseSeverity": "HIGH",
                  "confidentialityImpact": "HIGH",
                  "integrityImpact": "HIGH",
                  "privilegesRequired": "LOW",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2025-21791",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2025-02-27T17:57:16.236835Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-416",
                    "description": "CWE-416 Use After Free",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2025-02-27T17:57:17.808Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "include/net/l3mdev.h"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                },
                {
                  "lessThan": "20a3489b396764cc9376e32a9172bee26a89dc3b",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                },
                {
                  "lessThan": "5bb4228c32261d06e4fbece37ec3828bcc005b6b",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                },
                {
                  "lessThan": "c7574740be8ce68a57d0aece24987b9be2114c3c",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                },
                {
                  "lessThan": "c40cb5c03e37552d6eff963187109e2c3f78ef6f",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                },
                {
                  "lessThan": "022cac1c693add610ae76ede03adf4d9d5a2cf21",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                },
                {
                  "lessThan": "7b81425b517accefd46bee854d94954f5c57e019",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                },
                {
                  "lessThan": "6d0ce46a93135d96b7fa075a94a88fe0da8e8773",
                  "status": "affected",
                  "version": "a8e3e1a9f02094145580ea7920c6a1d9aabd5539",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "include/net/l3mdev.h"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "4.9"
                },
                {
                  "lessThan": "4.9",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.4.*",
                  "status": "unaffected",
                  "version": "5.4.291",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.10.*",
                  "status": "unaffected",
                  "version": "5.10.235",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.15.*",
                  "status": "unaffected",
                  "version": "5.15.179",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.1.*",
                  "status": "unaffected",
                  "version": "6.1.129",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.6.*",
                  "status": "unaffected",
                  "version": "6.6.79",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.12.*",
                  "status": "unaffected",
                  "version": "6.12.16",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.13.*",
                  "status": "unaffected",
                  "version": "6.13.4",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "6.14",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.4.291",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.10.235",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.15.179",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.1.129",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.6.79",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.12.16",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.13.4",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.14",
                      "versionStartIncluding": "4.9",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvrf: use RCU protection in l3mdev_l3_out()\n\nl3mdev_l3_out() can be called without RCU being held:\n\nraw_sendmsg()\n ip_push_pending_frames()\n  ip_send_skb()\n   ip_local_out()\n    __ip_local_out()\n     l3mdev_ip_out()\n\nAdd rcu_read_lock() / rcu_read_unlock() pair to avoid\na potential UAF."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:L - Both halves of the race are driven from the local system \u2014 a `sendmsg()` on a local socket for the read side, and RTNL link operations (VRF delete/unenslave) for the free side. A remote peer cannot induce the VRF teardown that arms the use-after-free.\nAC:L - The attacker controls both sides of the race and can loop them indefinitely: one thread sends UDP/raw packets out a VRF-enslaved device while another repeatedly unenslaves/deletes the VRF master, with preemption pressure raised at will. `do_vrf_del_slave()` widens the window further by unlinking the adjacency before clearing `IFF_L3MDEV_SLAVE`.\nPR:L - The transmit side needs no privileges at all (ordinary UDP sendmsg), and the VRF create/enslave/delete side needs only CAP_NET_ADMIN within a network namespace, which an unprivileged user obtains via `unshare -Urn`.\nUI:N - The attacker\u0027s own threads perform every step \u2014 socket sends and netlink link operations \u2014 with no victim action required.\nS:U - The use-after-free and its consequences are confined to the kernel\u0027s own security authority; no VM, IOMMU, or other trust boundary is crossed.\nC:H - The freed `netdev_adjacent` sits in a general kmalloc cache and is readily groomed, letting the attacker supply `upper-\u003edev`, after which `master-\u003el3mdev_ops` and `-\u003el3mdev_l3_out` are read from an attacker-chosen address \u2014 an arbitrary kernel read primitive.\nI:H - The same reclaimed object yields an indirect call through an attacker-controlled function pointer with `master` as the first argument, giving control-flow hijack and thus arbitrary kernel-state modification.\nA:H - Even unweaponized, dereferencing a stale adjacency entry and calling through garbage function pointers reliably oopses or panics the kernel, and the attacker can retrigger it at will."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-05T11:54:28.163Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/6ccaa5797f5362a2aad6baa6ddaf4715ac2dd51e"
            },
            {
              "url": "https://git.kernel.org/stable/c/20a3489b396764cc9376e32a9172bee26a89dc3b"
            },
            {
              "url": "https://git.kernel.org/stable/c/5bb4228c32261d06e4fbece37ec3828bcc005b6b"
            },
            {
              "url": "https://git.kernel.org/stable/c/c7574740be8ce68a57d0aece24987b9be2114c3c"
            },
            {
              "url": "https://git.kernel.org/stable/c/c40cb5c03e37552d6eff963187109e2c3f78ef6f"
            },
            {
              "url": "https://git.kernel.org/stable/c/022cac1c693add610ae76ede03adf4d9d5a2cf21"
            },
            {
              "url": "https://git.kernel.org/stable/c/7b81425b517accefd46bee854d94954f5c57e019"
            },
            {
              "url": "https://git.kernel.org/stable/c/6d0ce46a93135d96b7fa075a94a88fe0da8e8773"
            }
          ],
          "title": "vrf: use RCU protection in l3mdev_l3_out()",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2025-21791",
        "datePublished": "2025-02-27T02:18:29.014Z",
        "dateReserved": "2024-12-29T08:45:45.766Z",
        "dateUpdated": "2026-08-05T11:54:28.163Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.