GHSA-J5V6-9QH5-X594

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

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

net: bridge: mrp: fix uninitialised bytes on the wire

br_mrp_alloc_test_skb() builds MRP test frames on an skb from dev_alloc_skb(), which does not clear the linear data area. On the MRA ring-role branch the sub-option TLV header is appended with

sub_tlv = skb_put(skb, sizeof(*sub_tlv));
sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;

so sub_tlv->length is never written, and the two trailing alignment bytes are appended with a bare skb_put() that does not clear them either. The neighbouring oui and sub_opt regions are explicitly zeroed, so three uninitialised bytes are left in every MRA MRP_Test frame that goes out.

Put the sub-option TLV header and the alignment padding in a single skb_put_zero(), which clears both. The AUTO_MGR sub-TLV carries no payload, so the zeroed length field is already the value it should have.

Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-74659"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:39Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mrp: fix uninitialised bytes on the wire\n\nbr_mrp_alloc_test_skb() builds MRP test frames on an skb from\ndev_alloc_skb(), which does not clear the linear data area.  On the MRA\nring-role branch the sub-option TLV header is appended with\n\n\tsub_tlv = skb_put(skb, sizeof(*sub_tlv));\n\tsub_tlv-\u003etype = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;\n\nso sub_tlv-\u003elength is never written, and the two trailing alignment bytes\nare appended with a bare skb_put() that does not clear them either.  The\nneighbouring oui and sub_opt regions are explicitly zeroed, so three\nuninitialised bytes are left in every MRA MRP_Test frame that goes out.\n\nPut the sub-option TLV header and the alignment padding in a single\nskb_put_zero(), which clears both.  The AUTO_MGR sub-TLV carries no\npayload, so the zeroed length field is already the value it should have.",
  "id": "GHSA-j5v6-9qh5-x594",
  "modified": "2026-08-22T18:30:28Z",
  "published": "2026-08-22T18:30:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74659"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/014c062d23c63ec77ef2cf17a0d9363c7441cc94"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/06d58b8d2f053ced82e01efaeb6e7c82891eed58"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5912cf1822fbe53ae275c147868740eb384a5d3e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/63488dba65ef91373ef616575b32eb0eb21459f4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ebc23ff03668042e0b0e4034bb1518d36198d9e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a5e385eeb2d6dbbbdebfa050e67c34734ae12693"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e08665218040f8e312abe40f74543186f3c2c941"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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.