{"id":"CVE-2026-53012","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: fix IPv6 route referencing IPv4 nexthop\n\nsyzbot reported a panic [1] [2].\n\nWhen an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag\nof all groups…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: fix IPv6 route referencing IPv4 nexthop\n\nsyzbot reported a panic [1] [2].\n\nWhen an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag\nof all groups…","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-476"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.3, < 5.10.258","linux_kernel >= 5.11, < 5.15.209","linux_kernel >= 5.16, < 6.1.175","linux_kernel >= 6.2, < 6.6.141","linux_kernel >= 6.7, < 6.12.91","linux_kernel >= 6.13, < 6.18.33","linux_kernel >= 6.19, < 7.0.10"],"patched":["linux_kernel 7.0.10"],"published":"2026-06-24","updated":"2026-09-08","sourceUpdated":"2026-09-08T09:18:13.880","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53012","references":[{"url":"https://git.kernel.org/stable/c/29c95185ba32b621fbc3800fb86e7dc3edf5c2be","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/613c8f4a501421dd258b07ea614205d4e16ec845","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6275796f22bb382f3e9aa58ed0b4ef7bdad78cb8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9c2d6770a5f4545a307eb66979bef7656a34d621","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/aaac3bed034239e1d75732211d9b05f30b0b4f35","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ad85961004fd4bd2f31209ac4b07612c6cefb9e7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b3b7e850e1541f0520c4a12ec884255c30427ff6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ceffe81a0be92afc0cd1340bc8ca46559cce9bb4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00133,"epssPercentile":0.03225,"ingestedAt":"2026-07-11T19:15:11.719Z","slug":"CVE-2026-53012","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: fix IPv6 route referencing IPv4 nexthop\n\nsyzbot reported a panic [1] [2].\n\nWhen an IPv6 nexthop is replaced with an IPv4 nexthop, the has_v4 flag\nof all groups containing this nexthop is not updated. This is because\nnh_group_v4_update is only called when replacing AF_INET to AF_INET6,\nbut the reverse direction (AF_INET6 to AF_INET) is missed.\n\nThis allows a stale has_v4=false to bypass fib6_check_nexthop, causing\nIPv6 routes to be attached to groups that effectively contain only AF_INET\nmembers. Subsequent route lookups then call nexthop_fib6_nh() which\nreturns NULL for the AF_INET member, leading to a NULL pointer\ndereference.\n\nFix by calling nh_group_v4_update whenever the family changes, not just\nAF_INET to AF_INET6.\n\nReproducer:\n\t# AF_INET6 blackhole\n\tip -6 nexthop add id 1 blackhole\n\t# group with has_v4=false\n\tip nexthop add id 100 group 1\n\t# replace with AF_INET (no -6), has_v4 stays false\n\tip nexthop replace id 1 blackhole\n\t# pass stale has_v4 check\n\tip -6 route add 2001:db8::/64 nhid 100\n\t# panic\n\tping -6 2001:db8::1\n\n[1] https://syzkaller.appspot.com/bug?id=e17283eb2f8dcf3dd9b47fe6f67a95f71faadad0\n[2] https://syzkaller.appspot.com/bug?id=8699b6ae54c9f35837d925686208402949e12ef3\n\n## Affected\n\n- `linux_kernel >= 5.3, < 5.10.258`\n- `linux_kernel >= 5.11, < 5.15.209`\n- `linux_kernel >= 5.16, < 6.1.175`\n- `linux_kernel >= 6.2, < 6.6.141`\n- `linux_kernel >= 6.7, < 6.12.91`\n- `linux_kernel >= 6.13, < 6.18.33`\n- `linux_kernel >= 6.19, < 7.0.10`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.10`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":5315,"id":"CVE-2026-53012","ts":1788887264666,"field":"cvss","old":null,"new":"5.5"},{"seq":5314,"id":"CVE-2026-53012","ts":1788887264666,"field":"severity","old":"none","new":"medium"},{"seq":4198,"id":"CVE-2026-53012","ts":1788886379491,"field":"cvss","old":"5.5","new":null},{"seq":4197,"id":"CVE-2026-53012","ts":1788886379491,"field":"severity","old":"medium","new":"none"},{"seq":2959,"id":"CVE-2026-53012","ts":1788883044594,"field":"cvss","old":null,"new":"5.5"},{"seq":2958,"id":"CVE-2026-53012","ts":1788883044594,"field":"severity","old":"none","new":"medium"},{"seq":1988,"id":"CVE-2026-53012","ts":1788882448796,"field":"cvss","old":"5.5","new":null},{"seq":1987,"id":"CVE-2026-53012","ts":1788882448796,"field":"severity","old":"medium","new":"none"},{"seq":257,"id":"CVE-2026-53012","ts":1788881642909,"field":"cvss","old":null,"new":"5.5"},{"seq":256,"id":"CVE-2026-53012","ts":1788881642909,"field":"severity","old":"none","new":"medium"}]}