CVE-2026-53366 (GCVE-0-2026-53366)

Vulnerability from cvelistv5 – Published: 2026-07-16 05:13 – Updated: 2026-10-19 20:07
VLAI
Title
ipv4: account for fraggap on the paged allocation path
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv4: account for fraggap on the paged allocation path In __ip_append_data(), when the paged-allocation branch is taken, alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap, but the fraggap bytes carried over from the previous skb are copied into the new skb's linear area at offset transhdrlen by the subsequent skb_copy_and_csum_bits(). The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic.
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 2026-10-16 15:29 UTC
CWE
  • CWE-131 - Incorrect Calculation of Buffer Size
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6996 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 8eb77cc73977d88787b37c92831b1c242e035396 , < 5c6375bced6147ec2e460ee3b653f4860d5ecdc2 (git)
Affected: 8eb77cc73977d88787b37c92831b1c242e035396 , < ce494707a9c07f27c219ca67f3e138061f53d9b3 (git)
Affected: 8eb77cc73977d88787b37c92831b1c242e035396 , < a9c24eda24bd15f432e37824e6fc440977cb241c (git)
Affected: 8eb77cc73977d88787b37c92831b1c242e035396 , < 77798d7be6ef71e72fb6fc8a2901bf74ebc9706f (git)
Affected: 8eb77cc73977d88787b37c92831b1c242e035396 , < c04d9ece23deb9e26c19f9ca215e98b3295aa1bb (git)
Affected: 8eb77cc73977d88787b37c92831b1c242e035396 , < eca856950f7cb1a221e02b99d758409f2c5cec42 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.144 , ≤ 6.6.* (semver)
Unaffected: 6.12.95 , ≤ 6.12.* (semver)
Unaffected: 6.18.38 , ≤ 6.18.* (semver)
Unaffected: 7.1.3 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/eca856950f7cb1a221e02b99d758409f2c5cec42"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          },
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-131"
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-09-10T03:16:41+00:00",
      "cve": "CVE-2026-53366",
      "id": "CVE-2026-53366",
      "initial_release_date": "2026-07-16T00:00:00+00:00",
      "product_status:fixed": "919",
      "product_status:known_affected": "22",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ipv4: account for fraggap on the paged allocation path",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53366.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-53366",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-10-16T15:29:22.182830Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-10-16T15:29:23.415Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "net/ipv4/ip_output.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "5c6375bced6147ec2e460ee3b653f4860d5ecdc2",
                  "status": "affected",
                  "version": "8eb77cc73977d88787b37c92831b1c242e035396",
                  "versionType": "git"
                },
                {
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                  "status": "affected",
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                  "versionType": "git"
                },
                {
                  "lessThan": "a9c24eda24bd15f432e37824e6fc440977cb241c",
                  "status": "affected",
                  "version": "8eb77cc73977d88787b37c92831b1c242e035396",
                  "versionType": "git"
                },
                {
                  "lessThan": "77798d7be6ef71e72fb6fc8a2901bf74ebc9706f",
                  "status": "affected",
                  "version": "8eb77cc73977d88787b37c92831b1c242e035396",
                  "versionType": "git"
                },
                {
                  "lessThan": "c04d9ece23deb9e26c19f9ca215e98b3295aa1bb",
                  "status": "affected",
                  "version": "8eb77cc73977d88787b37c92831b1c242e035396",
                  "versionType": "git"
                },
                {
                  "lessThan": "eca856950f7cb1a221e02b99d758409f2c5cec42",
                  "status": "affected",
                  "version": "8eb77cc73977d88787b37c92831b1c242e035396",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "net/ipv4/ip_output.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "6.0"
                },
                {
                  "lessThan": "6.0",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.1.*",
                  "status": "unaffected",
                  "version": "6.1.178",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.6.*",
                  "status": "unaffected",
                  "version": "6.6.144",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.12.*",
                  "status": "unaffected",
                  "version": "6.12.95",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.18.*",
                  "status": "unaffected",
                  "version": "6.18.38",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "7.1.*",
                  "status": "unaffected",
                  "version": "7.1.3",
                  "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": "6.1.178",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.6.144",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.12.95",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.18.38",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "7.1.3",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "7.2",
                      "versionStartIncluding": "6.0",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: account for fraggap on the paged allocation path\n\nIn __ip_append_data(), when the paged-allocation branch is taken,\nalloclen and pagedlen are computed as\n\n\talloclen = fragheaderlen + transhdrlen;\n\tpagedlen = datalen - transhdrlen;\n\ndatalen already includes fraggap, but the fraggap bytes carried over\nfrom the previous skb are copied into the new skb\u0027s linear area at\noffset transhdrlen by the subsequent skb_copy_and_csum_bits(). The\nlinear area is therefore undersized by fraggap bytes while pagedlen is\noverstated by the same amount.\n\nThe non-paged branch sets alloclen to fraglen, which already accounts\nfor fraggap because datalen does. Bring the paged branch in line by\nadding fraggap to alloclen and subtracting it from pagedlen.\n\nAfter this adjustment, copy no longer collapses to -fraggap on the\npaged path, so remove the stale comment describing that old arithmetic."
            }
          ],
          "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 vulnerable code is reached while a local process constructs outgoing IPv4 UDP/raw/ping datagrams through sendmsg/splice/sendfile-style socket paths. I did not find a defensible received-packet or unauthenticated remote path that supplies the required cork/MSG_MORE-style fraggap conditions.\nAC:L - The attacker can choose UDP socket options/flags, payload sizes, corking/MSG_MORE behavior, and splice/zerocopy-style paged sends to reach the fraggap paged-allocation path. There is no race or external timing condition required.\nPR:L - A normal unprivileged local user can create IPv4 UDP sockets and use UDP_CORK/MSG_MORE/splice or related paged send paths; raw sockets are CAP_NET_RAW-gated but are not needed for the strongest local trigger. This is therefore basic local user privilege, not real administrator privilege.\nUI:N - No victim interaction is required once the attacker can run the local send/splice sequence. The vulnerable skb construction happens synchronously in the attacker-driven socket send path.\nS:U - The impact is within the same kernel security authority as the vulnerable IPv4 networking code. This is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The bug under-allocates/accounting for the linear skb area and can copy attacker-controlled fraggap bytes past skb-\u003eend into trailing skb_shared_info metadata. Kernel memory corruption of this kind is reasonably capable of being developed into information disclosure, so the higher severity confidentiality value is appropriate.\nI:H - The copied fraggap bytes corrupt kernel skb metadata past the intended buffer boundary. This is an out-of-bounds write in kernel heap/networking structures and is scored as high integrity impact.\nA:H - The corrupted skb metadata can crash or destabilize the kernel networking stack, and related negative-copy accounting can also produce severe send-path failure behavior. Kernel crash or oops potential is high availability impact."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-17T04:50:30.453Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/5c6375bced6147ec2e460ee3b653f4860d5ecdc2"
            },
            {
              "url": "https://git.kernel.org/stable/c/ce494707a9c07f27c219ca67f3e138061f53d9b3"
            },
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              "url": "https://git.kernel.org/stable/c/a9c24eda24bd15f432e37824e6fc440977cb241c"
            },
            {
              "url": "https://git.kernel.org/stable/c/77798d7be6ef71e72fb6fc8a2901bf74ebc9706f"
            },
            {
              "url": "https://git.kernel.org/stable/c/c04d9ece23deb9e26c19f9ca215e98b3295aa1bb"
            },
            {
              "url": "https://git.kernel.org/stable/c/eca856950f7cb1a221e02b99d758409f2c5cec42"
            }
          ],
          "title": "ipv4: account for fraggap on the paged allocation path",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2026-53366",
        "datePublished": "2026-07-16T05:13:40.893Z",
        "dateReserved": "2026-06-09T07:44:35.400Z",
        "dateUpdated": "2026-10-16T15:31:51.254Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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