FKIE_CVE-2026-72442

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:19
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: fix and simplify IP6IP6 tunnel handling Fix nf_flow_ip6_tunnel_proto() to use pskb_may_pull() instead of skb_header_pointer() to ensure the outer IPv6 header is in the skb headroom, which is required for subsequent packet processing. Move ctx->offset update inside the IPPROTO_IPV6 conditional block since it should only be adjusted when an IP6IP6 tunnel is actually detected. Simplify the rx path by removing ipv6_skip_exthdr() and checking ip6h->nexthdr directly, as the flowtable fast path only handles simple IP6IP6 encapsulation without extension headers. Drop the tunnel encapsulation limit destination option support from the tx path to match, since the rx path no longer handles extension headers. Remove the encap_limit parameter from nf_flow_offload_ipv6_forward(), nf_flow_tunnel_ip6ip6_push() and nf_flow_tunnel_v6_push(), along with the ipv6_tel_txoption struct and related headroom/MTU adjustments.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7f8d816a9aa2729d270418f00c9ef5e85bfc1b31
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f4c2d8668d85ed125985da663c824a9c25498257
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ip6_tunnel.c",
            "net/netfilter/nf_flow_table_ip.c",
            "tools/testing/selftests/net/netfilter/nft_flowtable.sh"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "7f8d816a9aa2729d270418f00c9ef5e85bfc1b31",
              "status": "affected",
              "version": "d98103575dcdd3a730e0901ab457791a9ac6930c",
              "versionType": "git"
            },
            {
              "lessThan": "f4c2d8668d85ed125985da663c824a9c25498257",
              "status": "affected",
              "version": "d98103575dcdd3a730e0901ab457791a9ac6930c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ip6_tunnel.c",
            "net/netfilter/nf_flow_table_ip.c",
            "tools/testing/selftests/net/netfilter/nft_flowtable.sh"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.0"
            },
            {
              "lessThan": "7.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nnetfilter: flowtable: fix and simplify IP6IP6 tunnel handling\n\nFix nf_flow_ip6_tunnel_proto() to use pskb_may_pull() instead of\nskb_header_pointer() to ensure the outer IPv6 header is in the skb\nheadroom, which is required for subsequent packet processing. Move\nctx-\u003eoffset update inside the IPPROTO_IPV6 conditional block since it\nshould only be adjusted when an IP6IP6 tunnel is actually detected.\nSimplify the rx path by removing ipv6_skip_exthdr() and checking\nip6h-\u003enexthdr directly, as the flowtable fast path only handles simple\nIP6IP6 encapsulation without extension headers.\nDrop the tunnel encapsulation limit destination option support from the\ntx path to match, since the rx path no longer handles extension headers.\nRemove the encap_limit parameter from nf_flow_offload_ipv6_forward(),\nnf_flow_tunnel_ip6ip6_push() and nf_flow_tunnel_v6_push(), along with\nthe ipv6_tel_txoption struct and related headroom/MTU adjustments."
    }
  ],
  "id": "CVE-2026-72442",
  "lastModified": "2026-08-17T06:19:11.597",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:22:18.063",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7f8d816a9aa2729d270418f00c9ef5e85bfc1b31"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f4c2d8668d85ed125985da663c824a9c25498257"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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