In 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

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < 8c10778ec674b67a07ea042fcba64270f3f38a5a
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < 2731efa6364e47934c96eb69e01ea131e8af8030
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < 00c06ef8c018493943891a7d0ca82b71b24f3180
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < c141f69d0a0fb16964dbc293650047e69bda8af7
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < f2e6596d10783557aeb9668da2a3b4d19deb2001
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < 1c4f67c89fd27c4df4c70b135c2c59627698b3c0
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < 4ac981a8b7ce7aec99a52d08f8a8953e8e120067
764dd163ac922f8683b5bcd3007251ce7b26cd33 affected < 86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d
Linux Linux affected
Version Status Constraints
5.3 affected —
0 unaffected < 5.3
5.10.261 unaffected ≤ 5.10.*
5.15.212 unaffected ≤ 5.15.*
6.1.178 unaffected ≤ 6.1.*
6.6.145 unaffected ≤ 6.6.*
6.12.97 unaffected ≤ 6.12.*
6.18.40 unaffected ≤ 6.18.*
7.1.5 unaffected ≤ 7.1.*
7.2-rc4 unaffected ≤ *

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References
Link Providers
https://git.kernel.org/stable/c/00c06ef8c018493943891a7d0ca82b71b24f3180 cve-icon
https://git.kernel.org/stable/c/1c4f67c89fd27c4df4c70b135c2c59627698b3c0 cve-icon
https://git.kernel.org/stable/c/2731efa6364e47934c96eb69e01ea131e8af8030 cve-icon
https://git.kernel.org/stable/c/4ac981a8b7ce7aec99a52d08f8a8953e8e120067 cve-icon
https://git.kernel.org/stable/c/86f3ce81dd2b4b0aa2c3016c989a943e4b1b643d cve-icon
https://git.kernel.org/stable/c/8c10778ec674b67a07ea042fcba64270f3f38a5a cve-icon
https://git.kernel.org/stable/c/c141f69d0a0fb16964dbc293650047e69bda8af7 cve-icon
https://git.kernel.org/stable/c/f2e6596d10783557aeb9668da2a3b4d19deb2001 cve-icon
History

Mon, 27 Jul 2026 20:30:00 +0000

Type Values Removed Values Added
Description In 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
Title netfilter: bridge: fix stale prevhdr pointer in br_ip6_fragment()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-27T20:10:41.726Z

Reserved: 2026-07-19T15:36:31.796Z

Link: CVE-2026-64554

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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