nexthop: fix IPv6 route referencing IPv4 nexthop
Summary
| CVE | CVE-2026-53012 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-24 17:17:12 UTC |
| Updated | 2026-07-10 19:24:19 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: nexthop: fix IPv6 route referencing IPv4 nexthop syzbot reported a panic [1] [2]. When an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag of all groups containing this nexthop is not updated. This is because nh_group_v4_update is only called when replacing AF_INET to AF_INET6, but the reverse direction (AF_INET6 to AF_INET) is missed. This allows a stale has_v4=false to bypass fib6_check_nexthop, causing IPv6 routes to be attached to groups that effectively contain only AF_INET members. Subsequent route lookups then call nexthop_fib6_nh() which returns NULL for the AF_INET member, leading to a NULL pointer dereference. Fix by calling nh_group_v4_update whenever the family changes, not just AF_INET to AF_INET6. Reproducer: # AF_INET6 blackhole ip -6 nexthop add id 1 blackhole # group with has_v4=false ip nexthop add id 100 group 1 # replace with AF_INET (no -6), has_v4 stays false ip nexthop replace id 1 blackhole # pass stale has_v4 check ip -6 route add 2001:db8::/64 nhid 100 # panic ping -6 2001:db8::1 [1] https://syzkaller.appspot.com/bug?id=e17283eb2f8dcf3dd9b47fe6f67a95f71faadad0 [2] https://syzkaller.appspot.com/bug?id=8699b6ae54c9f35837d925686208402949e12ef3 |
Risk And Classification
EPSS: 0.001850000 probability, percentile 0.082780000 (date 2026-07-12)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f ceffe81a0be92afc0cd1340bc8ca46559cce9bb4 git | Not specified |
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f 9c2d6770a5f4545a307eb66979bef7656a34d621 git | Not specified |
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f 6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8 git | Not specified |
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f aaac3bed034239e1d75732211d9b05f30b0b4f35 git | Not specified |
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f ad85961004fd4bd2f31209ac4b07612c6cefb9e7 git | Not specified |
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f 613c8f4a501421dd258b07ea614205d4e16ec845 git | Not specified |
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f b3b7e850e1541f0520c4a12ec884255c30427ff6 git | Not specified |
| CNA | Linux | Linux | affected 7bf4796dd09984ad1612877a82d0d139c70ae27f 29c95185ba32b621fbc3800fb86e7dc3edf5c2be git | Not specified |
| CNA | Linux | Linux | affected 5.3 | Not specified |
| CNA | Linux | Linux | unaffected 5.3 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.258 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.209 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.175 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.141 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.91 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.33 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0.10 7.0.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/29c95185ba32b621fbc3800fb86e7dc3edf5c2be | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/aaac3bed034239e1d75732211d9b05f30b0b4f35 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/b3b7e850e1541f0520c4a12ec884255c30427ff6 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/9c2d6770a5f4545a307eb66979bef7656a34d621 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/613c8f4a501421dd258b07ea614205d4e16ec845 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/ceffe81a0be92afc0cd1340bc8ca46559cce9bb4 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/ad85961004fd4bd2f31209ac4b07612c6cefb9e7 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.