FKIE_CVE-2026-74657

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-27 13:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops fib_nlmsg_size() still estimates nexthop space as if every gateway is encoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an IPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA. As a result, route notifications can allocate an skb that is too small. fib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the WARN_ON() that marks such failures as a fib_nlmsg_size() bug. With panic_on_warn set, this becomes a kernel panic. Mirror the actual nexthop dump layout in fib_nlmsg_size(): account for IPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop layout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is actually present.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0f0ca602941d0a81ae9514943ca06c55159c6385
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4a5dfbae5179f6574695012a980476254df2d295
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4ff9548d84945d2cbf9e4c207288063a200ea397
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5307a53599fa762c06e475ee4a375252074fd324
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7f80ad373ce4a7af5367ff273cea0f16e91387f3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9b22f13524fa0de0d963bbd3002df6c28bae3395
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a59edda6eda1252340354322d8ab318b2e9052fb
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/fib_semantics.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            },
            {
              "lessThan": "0f0ca602941d0a81ae9514943ca06c55159c6385",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            },
            {
              "lessThan": "5307a53599fa762c06e475ee4a375252074fd324",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            },
            {
              "lessThan": "7f80ad373ce4a7af5367ff273cea0f16e91387f3",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            },
            {
              "lessThan": "4a5dfbae5179f6574695012a980476254df2d295",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            },
            {
              "lessThan": "a59edda6eda1252340354322d8ab318b2e9052fb",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            },
            {
              "lessThan": "9b22f13524fa0de0d963bbd3002df6c28bae3395",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            },
            {
              "lessThan": "4ff9548d84945d2cbf9e4c207288063a200ea397",
              "status": "affected",
              "version": "d15662682db232da77136cd348f4c9df312ca6f9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/fib_semantics.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.2"
            },
            {
              "lessThan": "5.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.267",
              "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\nipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops\n\nfib_nlmsg_size() still estimates nexthop space as if every gateway is\nencoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an\nIPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA.\n\nAs a result, route notifications can allocate an skb that is too small.\nfib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the\nWARN_ON() that marks such failures as a fib_nlmsg_size() bug. With\npanic_on_warn set, this becomes a kernel panic.\n\nMirror the actual nexthop dump layout in fib_nlmsg_size(): account for\nIPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop\nlayout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is\nactually present."
    }
  ],
  "id": "CVE-2026-74657",
  "lastModified": "2026-08-27T13:18:36.153",
  "metrics": {},
  "published": "2026-08-22T16:16:39.333",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0f0ca602941d0a81ae9514943ca06c55159c6385"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4a5dfbae5179f6574695012a980476254df2d295"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4ff9548d84945d2cbf9e4c207288063a200ea397"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5307a53599fa762c06e475ee4a375252074fd324"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/57195f0ab5cfbb5ee0864e5aff15ceb48f5a5e28"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7f80ad373ce4a7af5367ff273cea0f16e91387f3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9b22f13524fa0de0d963bbd3002df6c28bae3395"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a59edda6eda1252340354322d8ab318b2e9052fb"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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