PT-2026-65229 · Linux · Linux
CVE-2026-64554
·
Published
2026-07-27
·
Updated
2026-07-27
None
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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
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Related Identifiers
Affected Products
Linux