{"id":"CVE-2026-64554","summary":"netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()\n\nbr_ip6_fragment() gets prevhdr, a pointer into the skb head, from\nip6_find_1stfragopt(), then calls skb_checksum_help().  For a cloned skb\nskb_checksum_help() reallocates the head via pskb_expand_head(), leaving\nprevhdr dangling.  It is later dereferenced in ip6_frag_next(), causing a\nuse-after-free write.\n\nSave prevhdr's offset before skb_checksum_help() and recompute it after,\nlike commit ef0efcd3bd3f (\"ipv6: Fix dangling pointer when ipv6\nfragment\").\n\n  BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857)\n  Write of size 1 at addr ffff888013ff5016 by task exploit/141\n  Call Trace:\n   ...\n   kasan_report (mm/kasan/report.c:595)\n   ip6_frag_next (net/ipv6/ip6_output.c:857)\n   br_ip6_fragment (net/ipv6/netfilter.c:212)\n   nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407)\n   nf_hook_slow (net/netfilter/core.c:619)\n   br_forward_finish (net/bridge/br_forward.c:66)\n   __br_forward (net/bridge/br_forward.c:115)\n   maybe_deliver (net/bridge/br_forward.c:191)\n   br_flood (net/bridge/br_forward.c:245)\n   br_handle_frame_finish (net/bridge/br_input.c:229)\n   br_handle_frame (net/bridge/br_input.c:442)\n   ...\n   packet_sendmsg (net/packet/af_packet.c:3114)\n   ...\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n  Kernel panic - not syncing: Fatal exception in interrupt","modified":"2026-08-18T03:31:24.922616638Z","published":"2026-07-27T20:10:41.726Z","related":["openSUSE-SU-2026:11476-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64554.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/00c06ef8c018493943891a7d0ca82b71b24f3180"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1c4f67c89fd27c4df4c70b135c2c59627698b3c0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2731efa6364e47934c96eb69e01ea131e8af8030"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4ac981a8b7ce7aec99a52d08f8a8953e8e120067"},{"type":"WEB","url":"https://git.kernel.org/stable/c/86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8c10778ec674b67a07ea042fcba64270f3f38a5a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c141f69d0a0fb16964dbc293650047e69bda8af7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f2e6596d10783557aeb9668da2a3b4d19deb2001"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64554.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64554"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"764dd163ac922f8683b5bcd3007251ce7b26cd33"},{"fixed":"8c10778ec674b67a07ea042fcba64270f3f38a5a"},{"fixed":"2731efa6364e47934c96eb69e01ea131e8af8030"},{"fixed":"00c06ef8c018493943891a7d0ca82b71b24f3180"},{"fixed":"c141f69d0a0fb16964dbc293650047e69bda8af7"},{"fixed":"f2e6596d10783557aeb9668da2a3b4d19deb2001"},{"fixed":"1c4f67c89fd27c4df4c70b135c2c59627698b3c0"},{"fixed":"4ac981a8b7ce7aec99a52d08f8a8953e8e120067"},{"fixed":"86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64554.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.3.0"},{"fixed":"5.10.261"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.212"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.178"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.97"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64554.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}