CVE-2026-74664 (GCVE-0-2026-74664)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-22 15:32
VLAI
Title
net: openvswitch: reallocate update replies for mismatched IDs
Summary
In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reallocate update replies for mismatched IDs ovs_flow_cmd_new() preallocates the optional reply skb before it takes ovs_mutex and before it knows which existing flow will be updated. That is normally fine because the skb is sized from the request flow identifier. That identifier also becomes the inserted flow's identifier. For updates, however, a request with a UFID may miss the UFID lookup and then fall back to the flow key lookup. That lookup can legitimately find an existing key-identified flow. UFIDs are optional and the flow key is the primary identifier. For echoed replies, ovs_flow_cmd_fill_info() writes the matched flow's identifier, not the request identifier used for the preallocation. A short request UFID can therefore leave too little room for the key identifier. The fill can then fail with -EMSGSIZE and hit the BUG_ON(error < 0) in the update path. Once the update target has been resolved, reallocate the reply skb if the matched flow needs a larger reply than the request identifier allowed. Do this before replacing the actions so the request can still fail cleanly if the rare extra allocation fails.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < bd8ca84d48cd9a4f6fc63df26512c55e1d339927 (git)
Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < 00f987f066e802793a37dd2167459e67cf2cf2ec (git)
Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < 696a0b9435fce9cf4f1e9ba7f6afa6bee96c97fc (git)
Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < 87d0c0040b5d4b61de51ae39132c4c46709f2f77 (git)
Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < 69f40ccf85074981340847d650a9cbf9adabfbbe (git)
Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < 23716dd9d8d46a5908536b73dc085e62f2b5c237 (git)
Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < 20751193d83be2e9735d4faee71375691c09cd13 (git)
Affected: 74ed7ab9264c54471c7f057409d352052820d750 , < 5d1c224dd914579524a183a514c12b95095d12ce (git)
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Linux Linux Affected: 4.0
Unaffected: 0 , < 4.0 (semver)
Unaffected: 5.10.265 , ≤ 5.10.* (semver)
Unaffected: 5.15.216 , ≤ 5.15.* (semver)
Unaffected: 6.1.183 , ≤ 6.1.* (semver)
Unaffected: 6.6.152 , ≤ 6.6.* (semver)
Unaffected: 6.12.104 , ≤ 6.12.* (semver)
Unaffected: 6.18.45 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: reallocate update replies for mismatched IDs\n\novs_flow_cmd_new() preallocates the optional reply skb before it takes\novs_mutex and before it knows which existing flow will be updated.\n\nThat is normally fine because the skb is sized from the request flow\nidentifier.  That identifier also becomes the inserted flow\u0027s identifier.\nFor updates, however, a request with a UFID may miss the UFID lookup and\nthen fall back to the flow key lookup.  That lookup can legitimately find\nan existing key-identified flow.  UFIDs are optional and the flow key is\nthe primary identifier.\n\nFor echoed replies, ovs_flow_cmd_fill_info() writes the matched flow\u0027s\nidentifier, not the request identifier used for the preallocation.  A short\nrequest UFID can therefore leave too little room for the key identifier.\nThe fill can then fail with -EMSGSIZE and hit the BUG_ON(error \u003c 0) in the\nupdate path.\n\nOnce the update target has been resolved, reallocate the reply skb if the\nmatched flow needs a larger reply than the request identifier allowed.  Do\nthis before replacing the actions so the request can still fail cleanly if\nthe rare extra allocation fails."
        }
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    "cveId": "CVE-2026-74664",
    "datePublished": "2026-08-22T15:32:36.616Z",
    "dateReserved": "2026-08-15T05:44:03.924Z",
    "dateUpdated": "2026-08-22T15:32:36.616Z",
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UFIDs are optional and the flow key is\\nthe primary identifier.\\n\\nFor echoed replies, ovs_flow_cmd_fill_info() writes the matched flow\u0027s\\nidentifier, not the request identifier used for the preallocation.  A short\\nrequest UFID can therefore leave too little room for the key identifier.\\nThe fill can then fail with -EMSGSIZE and hit the BUG_ON(error \u003c 0) in the\\nupdate path.\\n\\nOnce the update target has been resolved, reallocate the reply skb if the\\nmatched flow needs a larger reply than the request identifier allowed.  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    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-24T09:08:57+00:00",
      "cve": "CVE-2026-74664",
      "id": "CVE-2026-74664",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net: openvswitch: reallocate update replies for mismatched IDs",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74664.json",
      "version": "3"
    }
  }
}



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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

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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.