netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64554
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-27 21:17:08 UTC
Updated2026-07-27 21:17:08 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment() br_ip6_fragment() gets prevhdr, a pointer into the skb head, from ip6_find_1stfragopt(), then calls skb_checksum_help(). For a cloned skb skb_checksum_help() reallocates the head via pskb_expand_head(), leaving prevhdr dangling. It is later dereferenced in ip6_frag_next(), causing a use-after-free write. Save prevhdr's offset before skb_checksum_help() and recompute it after, like commit ef0efcd3bd3f ("ipv6: Fix dangling pointer when ipv6 fragment"). BUG: KASAN: slab-use-after-free in ip6_frag_next (net/ipv6/ip6_output.c:857) Write of size 1 at addr ffff888013ff5016 by task exploit/141 Call Trace: ... kasan_report (mm/kasan/report.c:595) ip6_frag_next (net/ipv6/ip6_output.c:857) br_ip6_fragment (net/ipv6/netfilter.c:212) nf_ct_bridge_post (net/bridge/netfilter/nf_conntrack_bridge.c:407) nf_hook_slow (net/netfilter/core.c:619) br_forward_finish (net/bridge/br_forward.c:66) __br_forward (net/bridge/br_forward.c:115) maybe_deliver (net/bridge/br_forward.c:191) br_flood (net/bridge/br_forward.c:245) br_handle_frame_finish (net/bridge/br_input.c:229) br_handle_frame (net/bridge/br_input.c:442) ... packet_sendmsg (net/packet/af_packet.c:3114) ... do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Kernel panic - not syncing: Fatal exception in interrupt

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 8c10778ec674b67a07ea042fcba64270f3f38a5a git Not specified
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 2731efa6364e47934c96eb69e01ea131e8af8030 git Not specified
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 00c06ef8c018493943891a7d0ca82b71b24f3180 git Not specified
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 c141f69d0a0fb16964dbc293650047e69bda8af7 git Not specified
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 f2e6596d10783557aeb9668da2a3b4d19deb2001 git Not specified
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 1c4f67c89fd27c4df4c70b135c2c59627698b3c0 git Not specified
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 4ac981a8b7ce7aec99a52d08f8a8953e8e120067 git Not specified
CNA Linux Linux affected 764dd163ac922f8683b5bcd3007251ce7b26cd33 86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d git Not specified
CNA Linux Linux affected 5.3 Not specified
CNA Linux Linux unaffected 5.3 semver Not specified
CNA Linux Linux unaffected 5.10.261 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc4 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/1c4f67c89fd27c4df4c70b135c2c59627698b3c0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2731efa6364e47934c96eb69e01ea131e8af8030 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8c10778ec674b67a07ea042fcba64270f3f38a5a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c141f69d0a0fb16964dbc293650047e69bda8af7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/00c06ef8c018493943891a7d0ca82b71b24f3180 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4ac981a8b7ce7aec99a52d08f8a8953e8e120067 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f2e6596d10783557aeb9668da2a3b4d19deb2001 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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