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ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu() l3mdev_master_dev_rcu() can return NULL when the slave device is being un-slaved from a VRF. All other callers deal with this, but we lost the fallback to loopback in ip6_rt_pcpu_alloc() -> ip6_rt_get_dev_rcu() with commit 4832c30d5458 ("net: ipv6: put host and anycast routes on device with address"). KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] RIP: 0010:ip6_rt_pcpu_alloc (net/ipv6/route.c:1418) Call Trace: ip6_pol_route (net/ipv6/route.c:2318) fib6_rule_lookup (net/ipv6/fib6_rules.c:115) ip6_route_output_flags (net/ipv6/route.c:2607) vrf_process_v6_outbound (drivers/net/vrf.c:437) I was tempted to rework the un-slaving code to clear the flag first and insert synchronize_rcu() before we remove the upper. But looks like the explicit fallback to loopback_dev is an established pattern. And I guess avoiding the synchronize_rcu() is nice, too.

Announced Source revision 1
Original source ↗

CVE-2026-23304

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-2026-23304

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": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "d542e2ac7f9e288d49735be0775611547ca4e0ee",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "a73fe9f4ae84a239d5b2686f47a58c158aee2eb4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "4a48fe59f29f673a3d042d679f26629a9c3e29d4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "581800298313c9fd75e94985e6d37d21b7e35d34",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "3310fc11fc47387d1dd4759b0bc961643ea11c7f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "0b5a7826020706057cc5a9d9009e667027f221ee",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "ae88c8256547b63980770a9ea7be73a15900d27e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4832c30d5458387ff2533ff66fbde26ad8bb5a2d",
        "lessThan": "2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/ipv6/route.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.14"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.14",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.253",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.203",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.167",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.130",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.77",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.17",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.7",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/ipv6/route.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-23304

Source reference: /cveMetadata/cveId

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Event
#27221 · Revision 1
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