GHSA-8X8H-4G2V-QPF2

Vulnerability from github – Published: 2026-05-06 12:30 – Updated: 2026-05-08 15:31
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()

On the receive path, __ioam6_fill_trace_data() uses trace->nodelen to decide how much data to write for each node. It trusts this field as-is from the incoming packet, with no consistency check against trace->type (the 24-bit field that tells which data items are present). A crafted packet can set nodelen=0 while setting type bits 0-21, causing the function to write ~100 bytes past the allocated region (into skb_shared_info), which corrupts adjacent heap memory and leads to a kernel panic.

Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to derive the expected nodelen from the type field, and use it:

  • in ioam6_iptunnel.c (send path, existing validation) to replace the open-coded computation;
  • in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose nodelen is inconsistent with the type field, before any data is written.

Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to 0xff1ffc00).

Severity ?
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-43186"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-06T12:16:37Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()\n\nOn the receive path, __ioam6_fill_trace_data() uses trace-\u003enodelen\nto decide how much data to write for each node. It trusts this field\nas-is from the incoming packet, with no consistency check against\ntrace-\u003etype (the 24-bit field that tells which data items are\npresent). A crafted packet can set nodelen=0 while setting type bits\n0-21, causing the function to write ~100 bytes past the allocated\nregion (into skb_shared_info), which corrupts adjacent heap memory\nand leads to a kernel panic.\n\nAdd a shared helper ioam6_trace_compute_nodelen() in ioam6.c to\nderive the expected nodelen from the type field, and use it:\n\n  - in ioam6_iptunnel.c (send path, existing validation) to replace\n    the open-coded computation;\n  - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose\n    nodelen is inconsistent with the type field, before any data is\n    written.\n\nPer RFC 9197, bits 12-21 are each short (4-octet) fields, so they\nare included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to\n0xff1ffc00).",
  "id": "GHSA-8x8h-4g2v-qpf2",
  "modified": "2026-05-08T15:31:17Z",
  "published": "2026-05-06T12:30:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43186"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0591d6509c2ff13f09ea2998434aba0c0472e978"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/632d233cf2e64a46865ae2c064ae3c9df7c8864f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6db8b56eed62baacaf37486e83378a72635c04cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e90346a2f1e8917d5760a44a1f61c44e3b36d96b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ea3632aefc04205436868541638e26f4a74d5637"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f4d9d4b8fd839719d564651671e24c62c545c23b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fb3c662fafebc5b9d74417ed1de8759f6bb72143"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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