CVE-2026-53012nexthop: fix IPv6 route referencing IPv4 nexthop
- 5.5MediumCVSS base score
- 0.14%Exploitation in 30 daysEPSS · top 97% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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
Timeline
ID reserved
By Linux
- 15 days later
· 15 days later
Published
- 5 months later
· 5 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.14% · top 97% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < ceffe81a0be92afc0cd1340bc8ca46559cce9bb4
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < 9c2d6770a5f4545a307eb66979bef7656a34d621
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < 6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < aaac3bed034239e1d75732211d9b05f30b0b4f35
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < ad85961004fd4bd2f31209ac4b07612c6cefb9e7
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < 613c8f4a501421dd258b07ea614205d4e16ec845
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < b3b7e850e1541f0520c4a12ec884255c30427ff6
- affected 7bf4796dd09984ad1612877a82d0d139c70ae27f – < 29c95185ba32b621fbc3800fb86e7dc3edf5c2be
- affected 5.3
- unaffected < 5.3
- unaffected 5.10.258 – ≤ 5.10.*
- unaffected 5.15.209 – ≤ 5.15.*
- unaffected 6.1.175 – ≤ 6.1.*
- unaffected 6.6.141 – ≤ 6.6.*
- unaffected 6.12.91 – ≤ 6.12.*
- unaffected 6.18.33 – ≤ 6.18.*
- unaffected 7.0.10 – ≤ 7.0.*
- unaffected 7.1 – ≤ *
References
References10
- https://git.kernel.org/stable/c/ceffe81a0be92afc0cd1340bc8ca46559cce9bb4 (opens in a new tab)
- https://git.kernel.org/stable/c/9c2d6770a5f4545a307eb66979bef7656a34d621 (opens in a new tab)
- https://git.kernel.org/stable/c/6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8 (opens in a new tab)
- https://git.kernel.org/stable/c/aaac3bed034239e1d75732211d9b05f30b0b4f35 (opens in a new tab)
- https://git.kernel.org/stable/c/ad85961004fd4bd2f31209ac4b07612c6cefb9e7 (opens in a new tab)
- https://git.kernel.org/stable/c/613c8f4a501421dd258b07ea614205d4e16ec845 (opens in a new tab)
- https://git.kernel.org/stable/c/b3b7e850e1541f0520c4a12ec884255c30427ff6 (opens in a new tab)
- https://git.kernel.org/stable/c/29c95185ba32b621fbc3800fb86e7dc3edf5c2be (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-38880 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-53012)Record last updated .