{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-80976",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-80976"
  ],
  "published": "2026-09-11T19:47:07Z",
  "summary": "seg6: reset IP6CB after IPv6 decapsulation",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nseg6: reset IP6CB after IPv6 decapsulation\n\ndecap_and_validate() pulls the outer SRv6 headers and makes the inner\npacket the skb network header. The IPv6 control block still contains\nvalues collected while parsing the outer packet, including nhoff and\nextension-header flags.\n\nEnd.DX6 and End.DT6 route the inner IPv6 packet directly to the IPv6\ninput path. An unprivileged user can reach End.DT6 from a user and net\nnamespace by installing a local SID and injecting an outer packet with\nHop-by-Hop and Destination Options headers followed by an SRH and a\nminimal inner IPv6 packet.\n\nThe outer extension headers leave a large nhoff in IP6CB. After\ndecapsulation, ip6_protocol_deliver_rcu() uses that stale offset on the\ninner packet and reads beyond the skb head. KASAN reports:\n\n  BUG: KASAN: slab-out-of-bounds in ip6_protocol_deliver_rcu\n  ip6_protocol_deliver_rcu+0x1118/0x1450\n  ip6_input_finish+0x11b/0x240\n  seg6_local_input_core+0xed/0x2e0\n  lwtunnel_input+0x1e9/0x4e0\n  ipv6_rthdr_rcv+0x525f/0x6c50\n  ip6_protocol_deliver_rcu+0xcb7/0x1450\n\nBefore clearing IP6CB for an inner IPv6 packet, save its incoming\ninterface index and L3 slave state. Restore both after the clear and set\nnhoff to the inner IPv6 base-header nexthdr field.\n\nUse IP6CB(skb)->iif rather than skb->skb_iif because VRF processing can\nreplace skb_iif with the L3 master while IP6CB keeps the receiving\ninterface. Preserve IP6SKB_L3SLAVE for the same reason.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.188",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-80976"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d1f0d353358987ca87f21d8956e2d2854951130d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a0e2b0a3718f0cf9fb0ee41710b4a6348a7315c8"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9ae92198c24d7dacd4070e2f34f6e1ed3a63061c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/96c74420ac92930a7e0f21770818544eee4a93d7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2b154e96fcb3f01fd42765c64e0a56820fbc16eb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cfa186a0857a0f831dfca67b16bbc40ecfdf3280"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c73fb911e02b9a766c950bc9707f3e3a96ffd702"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f967455fb2a5a2079b9eb5823e9ccf359174bf9f"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-14T12:06:03Z"
  }
}