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CVE-2026-74747

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: ipvs: revalidate ihl to prevent out-of-bounds access While the outer IP header is already pulled into the skb head, we must be careful and revalidate the embedded headers after reading them from the skb frags to prevent out-of-bounds access. One such place reported by Sashiko is ip_vs_nat_icmp() where local process can change the ihl field and after skb_ensure_writable() we can see larger value which is a problem for the ip_send_check(cih) calls. Add check to drop the packet if the ihl field is changed.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-08-26 15:16:53.657000
Last modified
2026-10-30 13:20:05.720000
View original CVE JSON 
{
  "id": "CVE-2026-74747",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-08-26T15:16:53.657",
  "lastModified": "2026-10-30T13:20:05.720",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: revalidate ihl to prevent out-of-bounds access\n\nWhile the outer IP header is already pulled into the skb head,\nwe must be careful and revalidate the embedded headers after\nreading them from the skb frags to prevent out-of-bounds\naccess.\n\nOne such place reported by Sashiko is ip_vs_nat_icmp() where\nlocal process can change the ihl field and after\nskb_ensure_writable() we can see larger value which is a\nproblem for the ip_send_check(cih) calls.\n\nAdd check to drop the packet if the ihl field is changed."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "include/net/ip_vs.h",
            "net/netfilter/ipvs/ip_vs_core.c",
            "net/netfilter/ipvs/ip_vs_xmit.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "f55bb94946fb8ee6304590a731c39c1fbc3b28bc",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "2512289cbf58706fd558e8fccea4e28003a2af54",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "041b2303c8019394735c1f76c5138657bf660a7d",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "eb81c8e758f49e04391f77d9470a6232bb5f1c7a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "5365f012451fce2453f13a568dcb72ea534c1e4d",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "d93660df4dd1d116f608ada4a29a80a5d6f0a6ed",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "include/net/ip_vs.h",
            "net/netfilter/ipvs/ip_vs_core.c",
            "net/netfilter/ipvs/ip_vs_xmit.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "2.6.12",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "2.6.12",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.191",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.160",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.114",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.57",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1.10",
              "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
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T19:16:17.710947Z",
          "id": "CVE-2026-74747",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/041b2303c8019394735c1f76c5138657bf660a7d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2512289cbf58706fd558e8fccea4e28003a2af54",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5365f012451fce2453f13a568dcb72ea534c1e4d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d93660df4dd1d116f608ada4a29a80a5d6f0a6ed",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/eb81c8e758f49e04391f77d9470a6232bb5f1c7a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f55bb94946fb8ee6304590a731c39c1fbc3b28bc",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}