FKIE_CVE-2026-63992

Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-20 15:17
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: tunnels: do not assume transport header in iptunnel_pmtud_check_icmp() In some cases, iptunnel_pmtud_check_icmp() can be called while skb transport header is not set. This triggers an out-of-bound access, because (typeof(skb->transport_header))~0U is 65535. Access the icmp header based on IPv4 network header, after making sure icmp->type is present in skb linear part. Note that iptunnel_pmtud_check_icmpv6()) is fine.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/ip_tunnel_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5a92cb45e34749865d03daf8d3500f77b5f6644c",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "c7b7ec3e69e673c0d6b57f74d21da50c485c598e",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "7f4f7efe7f30edd29c4988de01728bf2398217e4",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "a096b6e34f602950af9a2b0856cd93a5f4c276d7",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "43368636c663cff6e59dde93cf4b8e43ac28eb93",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "cb549df9ce4ee15c9d5b19ddab12cf2128e4313c",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            },
            {
              "lessThan": "509323077ef79a26ba0c60bb556e45c12c398b2d",
              "status": "affected",
              "version": "4cb47a8644cc9eb8ec81190a50e79e6530d0297f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/ip_tunnel_core.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": "5.10.*",
              "status": "unaffected",
              "version": "5.10.259",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.210",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.93",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntunnels: do not assume transport header in iptunnel_pmtud_check_icmp()\n\nIn some cases, iptunnel_pmtud_check_icmp() can be called while\nskb transport header is not set.\n\nThis triggers an out-of-bound access, because\n(typeof(skb-\u003etransport_header))~0U is 65535.\n\nAccess the icmp header based on IPv4 network header,\nafter making sure icmp-\u003etype is present in skb linear part.\n\nNote that iptunnel_pmtud_check_icmpv6()) is fine."
    }
  ],
  "id": "CVE-2026-63992",
  "lastModified": "2026-07-20T15:17:00.760",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-19T16:17:38.700",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/43368636c663cff6e59dde93cf4b8e43ac28eb93"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/509323077ef79a26ba0c60bb556e45c12c398b2d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5a92cb45e34749865d03daf8d3500f77b5f6644c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7f4f7efe7f30edd29c4988de01728bf2398217e4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a096b6e34f602950af9a2b0856cd93a5f4c276d7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c7b7ec3e69e673c0d6b57f74d21da50c485c598e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cb549df9ce4ee15c9d5b19ddab12cf2128e4313c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e917d0c69f01af2bb4fbea2b66d560a53b3ac7ec"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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