CVE-2026-74659 (GCVE-0-2026-74659)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-22 15:32
VLAI
Title
net: bridge: mrp: fix uninitialised bytes on the wire
Summary
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.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6665 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f7458934b0791c39a001e4d902fc3bf697b439b5 , < 014c062d23c63ec77ef2cf17a0d9363c7441cc94 (git)
Affected: f7458934b0791c39a001e4d902fc3bf697b439b5 , < 7ebc23ff03668042e0b0e4034bb1518d36198d9e (git)
Affected: f7458934b0791c39a001e4d902fc3bf697b439b5 , < 06d58b8d2f053ced82e01efaeb6e7c82891eed58 (git)
Affected: f7458934b0791c39a001e4d902fc3bf697b439b5 , < a5e385eeb2d6dbbbdebfa050e67c34734ae12693 (git)
Affected: f7458934b0791c39a001e4d902fc3bf697b439b5 , < 5912cf1822fbe53ae275c147868740eb384a5d3e (git)
Affected: f7458934b0791c39a001e4d902fc3bf697b439b5 , < e08665218040f8e312abe40f74543186f3c2c941 (git)
Affected: f7458934b0791c39a001e4d902fc3bf697b439b5 , < 63488dba65ef91373ef616575b32eb0eb21459f4 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.14
Unaffected: 0 , < 5.14 (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)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bridge/br_mrp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "014c062d23c63ec77ef2cf17a0d9363c7441cc94",
              "status": "affected",
              "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
              "versionType": "git"
            },
            {
              "lessThan": "7ebc23ff03668042e0b0e4034bb1518d36198d9e",
              "status": "affected",
              "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
              "versionType": "git"
            },
            {
              "lessThan": "06d58b8d2f053ced82e01efaeb6e7c82891eed58",
              "status": "affected",
              "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
              "versionType": "git"
            },
            {
              "lessThan": "a5e385eeb2d6dbbbdebfa050e67c34734ae12693",
              "status": "affected",
              "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
              "versionType": "git"
            },
            {
              "lessThan": "5912cf1822fbe53ae275c147868740eb384a5d3e",
              "status": "affected",
              "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
              "versionType": "git"
            },
            {
              "lessThan": "e08665218040f8e312abe40f74543186f3c2c941",
              "status": "affected",
              "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
              "versionType": "git"
            },
            {
              "lessThan": "63488dba65ef91373ef616575b32eb0eb21459f4",
              "status": "affected",
              "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bridge/br_mrp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.14"
            },
            {
              "lessThan": "5.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.216",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.152",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.104",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.45",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-22T15:32:32.926Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/014c062d23c63ec77ef2cf17a0d9363c7441cc94"
        },
        {
          "url": "https://git.kernel.org/stable/c/7ebc23ff03668042e0b0e4034bb1518d36198d9e"
        },
        {
          "url": "https://git.kernel.org/stable/c/06d58b8d2f053ced82e01efaeb6e7c82891eed58"
        },
        {
          "url": "https://git.kernel.org/stable/c/a5e385eeb2d6dbbbdebfa050e67c34734ae12693"
        },
        {
          "url": "https://git.kernel.org/stable/c/5912cf1822fbe53ae275c147868740eb384a5d3e"
        },
        {
          "url": "https://git.kernel.org/stable/c/e08665218040f8e312abe40f74543186f3c2c941"
        },
        {
          "url": "https://git.kernel.org/stable/c/63488dba65ef91373ef616575b32eb0eb21459f4"
        }
      ],
      "title": "net: bridge: mrp: fix uninitialised bytes on the wire",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74659",
    "datePublished": "2026-08-22T15:32:32.926Z",
    "dateReserved": "2026-08-15T05:44:03.924Z",
    "dateUpdated": "2026-08-22T15:32:32.926Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74659",
      "date": "2026-10-14",
      "epss": "0.00215",
      "percentile": "0.1101"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-24T14:45:26.000Z",
      "cve": "CVE-2026-74659",
      "id": "msrc_CVE-2026-74659",
      "initial_release_date": "2026-08-24T01:11:56.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "net: bridge: mrp: fix uninitialised bytes on the wire",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74659.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/bridge/br_mrp.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "014c062d23c63ec77ef2cf17a0d9363c7441cc94",
                    "status": "affected",
                    "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "7ebc23ff03668042e0b0e4034bb1518d36198d9e",
                    "status": "affected",
                    "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "06d58b8d2f053ced82e01efaeb6e7c82891eed58",
                    "status": "affected",
                    "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "a5e385eeb2d6dbbbdebfa050e67c34734ae12693",
                    "status": "affected",
                    "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5912cf1822fbe53ae275c147868740eb384a5d3e",
                    "status": "affected",
                    "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "e08665218040f8e312abe40f74543186f3c2c941",
                    "status": "affected",
                    "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "63488dba65ef91373ef616575b32eb0eb21459f4",
                    "status": "affected",
                    "version": "f7458934b0791c39a001e4d902fc3bf697b439b5",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/bridge/br_mrp.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.14"
                  },
                  {
                    "lessThan": "5.14",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.216",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.183",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.152",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.104",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.45",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.1.*",
                    "status": "unaffected",
                    "version": "7.1.9",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.2",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "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."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet: bridge: mrp: corregir bytes no inicializados en la red\n\nbr_mrp_alloc_test_skb() construye tramas de prueba MRP en un skb de dev_alloc_skb(), que no borra el \u00e1rea de datos lineal. En la rama de rol de anillo MRA, la cabecera TLV de subopci\u00f3n se a\u00f1ade con\n\nsub_tlv = skb_put(skb, sizeof(sub_tlv));\nsub_tlv -\u003e type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;\n\npor lo que sub_tlv -\u003e length nunca se escribe, y los dos bytes de alineaci\u00f3n finales se a\u00f1aden con un skb_put() simple que tampoco los borra. Las regiones oui y sub_opt vecinas se ponen expl\u00edcitamente a cero, por lo que quedan tres bytes no inicializados en cada trama MRA MRP_Test que sale.\n\nPoner la cabecera TLV de subopci\u00f3n y el relleno de alineaci\u00f3n en un \u00fanico skb_put_zero(), que borra ambos. El sub-TLV AUTO_MGR no lleva carga \u00fatil, por lo que el campo de longitud puesto a cero ya es el valor que deber\u00eda tener."
          }
        ],
        "id": "CVE-2026-74659",
        "lastModified": "2026-10-14T13:10:00.187",
        "metrics": {},
        "published": "2026-08-22T16:16:39.613",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/014c062d23c63ec77ef2cf17a0d9363c7441cc94"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/06d58b8d2f053ced82e01efaeb6e7c82891eed58"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5912cf1822fbe53ae275c147868740eb384a5d3e"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/63488dba65ef91373ef616575b32eb0eb21459f4"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/7ebc23ff03668042e0b0e4034bb1518d36198d9e"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/a5e385eeb2d6dbbbdebfa050e67c34734ae12693"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/e08665218040f8e312abe40f74543186f3c2c941"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-24T16:24:36+00:00",
      "cve": "CVE-2026-74659",
      "id": "CVE-2026-74659",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net: bridge: mrp: fix uninitialised bytes on the wire",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74659.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




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

JSON

Loading timeline…




    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.