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
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6666 records in the last 180 days details
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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        }
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            "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."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:\n\nnet: openvswitch: reasignar respuestas de actualizaci\u00f3n para IDs no coincidentes\n\novs_flow_cmd_new() preasigna el skb de respuesta opcional antes de tomar ovs_mutex y antes de saber qu\u00e9 flujo existente se actualizar\u00e1.\n\nEsto normalmente est\u00e1 bien porque el skb se dimensiona a partir del identificador de flujo de la solicitud. Ese identificador tambi\u00e9n se convierte en el identificador del flujo insertado. Para las actualizaciones, sin embargo, una solicitud con un UFID puede fallar en la b\u00fasqueda de UFID y luego recurrir a la b\u00fasqueda de clave de flujo. Esa b\u00fasqueda puede encontrar leg\u00edtimamente un flujo existente identificado por clave. Los UFID son opcionales y la clave de flujo es el identificador principal.\n\nPara las respuestas con eco, ovs_flow_cmd_fill_info() escribe el identificador del flujo coincidente, no el identificador de la solicitud utilizado para la preasignaci\u00f3n. Un UFID de solicitud corto puede, por lo tanto, dejar muy poco espacio para el identificador de clave. El llenado puede entonces fallar con -EMSGSIZE y activar el BUG_ON(error \u003c 0) en la ruta de actualizaci\u00f3n.\n\nUna vez que se ha resuelto el objetivo de actualizaci\u00f3n, reasigne el skb de respuesta si el flujo coincidente necesita una respuesta m\u00e1s grande de lo que permit\u00eda el identificador de la solicitud. Haga esto antes de reemplazar las acciones para que la solicitud a\u00fan pueda fallar limpiamente si la rara asignaci\u00f3n adicional falla."
          }
        ],
        "id": "CVE-2026-74664",
        "lastModified": "2026-10-14T13:10:00.187",
        "metrics": {},
        "published": "2026-08-22T16:16:40.220",
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        "vulnStatus": "Received"
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    "redhat_vex": {
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      "current_release_date": "2026-08-24T09:08:57+00:00",
      "cve": "CVE-2026-74664",
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      "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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Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.