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

CVE-2026-72405 (GCVE-0-2026-72405)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:43
VLAI
Title
net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync
Summary
In the Linux kernel, the following vulnerability has been resolved: net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync Yue Sun reported a use-after-free and debugobjects warning in udp_tunnel_nic_device_sync_work() during concurrent device operations. The workqueue core clears the internal pending bit before invoking the worker. At that point, a concurrent thread can queue the work again. When the already running worker eventually clears the work_pending flag to 0, it mistakenly clears the flag for the newly queued instance. udp_tunnel_nic_unregister() then observes work_pending as 0 and frees the structure while the second work item is still active in the queue, leading to UAF. Fix this by returning early in udp_tunnel_nic_device_sync() if work_pending is already set, preventing redundant work queueing.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: cc4e3835eff474aa274d6e1d18f69d9d296d3b76 , < cee6688e5731c0591643521716d1a1a5c1a98bf8 (git)
Affected: cc4e3835eff474aa274d6e1d18f69d9d296d3b76 , < 9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7 (git)
Affected: cc4e3835eff474aa274d6e1d18f69d9d296d3b76 , < 54292b167466cdf42176b7b6f01da66c184deb12 (git)
Affected: cc4e3835eff474aa274d6e1d18f69d9d296d3b76 , < ecf69d4b43370c587e48d4d70289dbdb7e039d4d (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.9
Unaffected: 0 , < 5.9 (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/udp_tunnel_nic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "cee6688e5731c0591643521716d1a1a5c1a98bf8",
              "status": "affected",
              "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76",
              "versionType": "git"
            },
            {
              "lessThan": "9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7",
              "status": "affected",
              "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76",
              "versionType": "git"
            },
            {
              "lessThan": "54292b167466cdf42176b7b6f01da66c184deb12",
              "status": "affected",
              "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76",
              "versionType": "git"
            },
            {
              "lessThan": "ecf69d4b43370c587e48d4d70289dbdb7e039d4d",
              "status": "affected",
              "version": "cc4e3835eff474aa274d6e1d18f69d9d296d3b76",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/udp_tunnel_nic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.9"
            },
            {
              "lessThan": "5.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync\n\nYue Sun reported a use-after-free and debugobjects warning in\nudp_tunnel_nic_device_sync_work() during concurrent device operations.\n\nThe workqueue core clears the internal pending bit before invoking the\nworker. At that point, a concurrent thread can queue the work again.\nWhen the already running worker eventually clears the work_pending flag\nto 0, it mistakenly clears the flag for the newly queued instance.\nudp_tunnel_nic_unregister() then observes work_pending as 0 and frees\nthe structure while the second work item is still active in the queue,\nleading to UAF.\n\nFix this by returning early in udp_tunnel_nic_device_sync() if\nwork_pending is already set, preventing redundant work queueing."
        }
      ],
      "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 - The bug is reached only through local netlink/RTNL paths (VXLAN/Geneve tunnel socket create/delete, netdev feature updates, or netdev unregister) that queue udp_tunnel_nic_device_sync; remote UDP/VXLAN packets do not enter this offload management code.\nAC:L - An attacker can reliably win the race by running concurrent tunnel create/delete or netdev operations in multiple threads; both the double-queue and the premature free depend on attacker-controlled timing, not on uncontrollable system state.\nPR:L - Triggering udp_tunnel_notify_add/del_rx_port requires CAP_NET_ADMIN (e.g. ip link add/del vxlan/geneve), which unprivileged users can obtain in a user/network namespace via unshare; no remote or pre-auth network path exists.\nUI:N - Exploitation requires only programmatic tunnel or netdev manipulation via netlink; no victim user action such as opening a file or mounting a filesystem is needed.\nS:U - Impact is kernel heap corruption and potential privilege escalation within the same kernel/host security domain; it does not by itself cross a VM, container, or IOMMU boundary to another authority.\nC:H - The flaw is a use-after-free of struct udp_tunnel_nic; freed offload state can be reallocated and read through the still-queued work handler, enabling arbitrary kernel memory disclosure.\nI:H - UAF on the udp_tunnel_nic work item and its entries allows heap grooming and corrupting kernel objects/driver callbacks, supporting arbitrary write and potential kernel code execution.\nA:H - Use-after-free in a workqueue handler on a shared offload path can cause kernel oops/panic or wedged NIC offload during concurrent tunnel churn, producing total loss of availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:43:45.202Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/cee6688e5731c0591643521716d1a1a5c1a98bf8"
        },
        {
          "url": "https://git.kernel.org/stable/c/9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7"
        },
        {
          "url": "https://git.kernel.org/stable/c/54292b167466cdf42176b7b6f01da66c184deb12"
        },
        {
          "url": "https://git.kernel.org/stable/c/ecf69d4b43370c587e48d4d70289dbdb7e039d4d"
        }
      ],
      "title": "net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72405",
    "datePublished": "2026-08-15T05:56:29.466Z",
    "dateReserved": "2026-08-09T03:40:39.925Z",
    "dateUpdated": "2026-08-17T05:43:45.202Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-72405",
      "date": "2026-09-05",
      "epss": "0.00134",
      "percentile": "0.03229"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-23T14:51:02.000Z",
      "cve": "CVE-2026-72405",
      "id": "msrc_CVE-2026-72405",
      "initial_release_date": "2026-08-23T14:51:02.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-72405.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-72405\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:22:14.077\",\"lastModified\":\"2026-08-17T06:19:07.170\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync\\n\\nYue Sun reported a use-after-free and debugobjects warning in\\nudp_tunnel_nic_device_sync_work() during concurrent device operations.\\n\\nThe workqueue core clears the internal pending bit before invoking the\\nworker. At that point, a concurrent thread can queue the work again.\\nWhen the already running worker eventually clears the work_pending flag\\nto 0, it mistakenly clears the flag for the newly queued instance.\\nudp_tunnel_nic_unregister() then observes work_pending as 0 and frees\\nthe structure while the second work item is still active in the queue,\\nleading to UAF.\\n\\nFix this by returning early in udp_tunnel_nic_device_sync() if\\nwork_pending is already set, preventing redundant work queueing.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/ipv4/udp_tunnel_nic.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"cc4e3835eff474aa274d6e1d18f69d9d296d3b76\",\"lessThan\":\"cee6688e5731c0591643521716d1a1a5c1a98bf8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cc4e3835eff474aa274d6e1d18f69d9d296d3b76\",\"lessThan\":\"9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cc4e3835eff474aa274d6e1d18f69d9d296d3b76\",\"lessThan\":\"54292b167466cdf42176b7b6f01da66c184deb12\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"cc4e3835eff474aa274d6e1d18f69d9d296d3b76\",\"lessThan\":\"ecf69d4b43370c587e48d4d70289dbdb7e039d4d\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/ipv4/udp_tunnel_nic.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.9\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.9\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/54292b167466cdf42176b7b6f01da66c184deb12\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9075efb9b2c1d9d7a8285c937b64aa93ca0c41b7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cee6688e5731c0591643521716d1a1a5c1a98bf8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ecf69d4b43370c587e48d4d70289dbdb7e039d4d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T17:40:56+00:00",
      "cve": "CVE-2026-72405",
      "id": "CVE-2026-72405",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "232",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net: udp_tunnel: prevent double queueing in udp_tunnel_nic_device_sync",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72405.json",
      "version": "3"
    }
  }
}



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.