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ipv4: fib: Don't ignore error route in local/main tables.

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: Don't ignore error route in local/main tables. When CONFIG_IP_MULTIPLE_TABLES is enabled but no rule is added, fib_lookup() performs route lookup directly on two tables. Since the first lookup does not properly bail out, the result of an error route in the merged local/main table could be overwritten by another route in the default table: # unshare -n # ip link set lo up # ip route add 192.168.0.0/24 dev lo table 253 # ip route add unreachable 192.168.0.0/24 # ip route get 192.168.0.1 192.168.0.1 dev lo table default uid 0 cache Once a random rule is added, the error route is respected: # ip rule add table 0 # ip rule del table 0 # ip route get 192.168.0.1 RTNETLINK answers: No route to host Let's fix the inconsistent behaviour.

Announced Group revision 1
Original source ↗

CVE-2026-72421

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-72421

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "a29e95fbc51e8a1b932773fd0e259b2080881443",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "5ae18d87a45698e8244d0fcba64c658c35a7dd3d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "9127589aabdee588278e8d0d0bd3709a760a92c8",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "49eaf1403201357762d745a35882fb734107d763",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "fd25996f57a95d56bc568c89b4921edcf334b7d8",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "828fad4fd418bcdb9f5d66fec0d184c52a85ec31",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "a668fa160247d7bbe921548cb845f607b8b9305f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f4530fa574df4d833506c53697ed1daa0d390bf4",
        "lessThan": "b72f0db64205d9ce462038ba995d5d31eff32dc1",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "include/net/ip_fib.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.6"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.6",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.261",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.212",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/ip_fib.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-72421

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#33049 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement

Revision history

  1. CVE-2026-72421 · Revision 1Source updated