GHSA-2FQW-FH97-QVMC

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31
VLAI
Details

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

ip6_tunnel: clear skb2->cb[] in ip6ip6_err()

ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the quoted inner IPv6 packet, and then passes the clone to icmpv6_send(). The clone still carries the outer packet's inet6_skb_parm in skb->cb.

If the outer packet had a Home Address Option, IP6CB(skb2)->dsthao remains non-zero after skb_pull(). icmpv6_send() later calls mip6_addr_swap(), which uses that stale dsthao offset against the quoted inner packet. A malformed inner destination-options header can then make the HAO lookup and address swap run past the end of the quoted packet and corrupt skb_shared_info.

Clear skb2->cb[] before pulling the quoted inner IPv6 packet so the reply path does not reuse metadata left by the outer IPv6 stack.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-74597"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:32Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nip6_tunnel: clear skb2-\u003ecb[] in ip6ip6_err()\n\nip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the\nquoted inner IPv6 packet, and then passes the clone to icmpv6_send().\nThe clone still carries the outer packet\u0027s inet6_skb_parm in skb-\u003ecb.\n\nIf the outer packet had a Home Address Option, IP6CB(skb2)-\u003edsthao\nremains non-zero after skb_pull(). icmpv6_send() later calls\nmip6_addr_swap(), which uses that stale dsthao offset against the quoted\ninner packet. A malformed inner destination-options header can then make\nthe HAO lookup and address swap run past the end of the quoted packet\nand corrupt skb_shared_info.\n\nClear skb2-\u003ecb[] before pulling the quoted inner IPv6 packet so the\nreply path does not reuse metadata left by the outer IPv6 stack.",
  "id": "GHSA-2fqw-fh97-qvmc",
  "modified": "2026-08-25T06:31:21Z",
  "published": "2026-08-22T18:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74597"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0dadb0620ab65949a8bc2439dd28ea3c942fe87d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/44fe898df302e91c5ee5acbc71ffa74e78e6c183"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/484134e1eb07d700a73b1e4bbf3fb503e299be60"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4eb15c465337b18f44716c499cd6ad63eee0ad54"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/64e41736a26f37ab6215bc2e6df125df05aceb08"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b6816536a2990c0db44a26130a03e40b441e829b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f803c086399da277b5d0ff36a107d0f162751800"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbf40faa0414b753212494ad197542002e66ed9e"
    }
  ],
  "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"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.