FKIE_CVE-2026-74659

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-22 16:16
Severity
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/014c062d23c63ec77ef2cf17a0d9363c7441cc94
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/06d58b8d2f053ced82e01efaeb6e7c82891eed58
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5912cf1822fbe53ae275c147868740eb384a5d3e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/63488dba65ef91373ef616575b32eb0eb21459f4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7ebc23ff03668042e0b0e4034bb1518d36198d9e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a5e385eeb2d6dbbbdebfa050e67c34734ae12693
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e08665218040f8e312abe40f74543186f3c2c941
Impacted products
Vendor Product Version
To clipboard 

{
  "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."
    }
  ],
  "id": "CVE-2026-74659",
  "lastModified": "2026-08-22T16:16:39.613",
  "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"
}



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