PT-2026-61396 · Linux · Linux

CVE-2026-64079

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Published

2026-07-19

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Updated

2026-07-19

None

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In the Linux kernel, the following vulnerability has been resolved:
netfilter: x tables: allocate hook ops while under mutex
arp/ip(6)t register table() add the table to the per-netns list via xt register table() before allocating the per-netns hook ops copy via kmemdup array(). This leaves a window where the table is visible in the list with ops=NULL.
If the pernet exit happens runs concurrently the pre exit callback finds the table via xt find table() and passes the NULL ops pointer to nf unregister net hooks(), causing a NULL dereference:
general protection fault in nf unregister net hooks+0xbc/0x150 RIP: nf unregister net hooks (net/netfilter/core.c:613) Call Trace: ipt unregister table pre exit iptable mangle net pre exit ops pre exit list cleanup net
Fix by moving the ops allocation into the xtables core so the table is never in the list without valid ops. Also ensure the table is no longer processing packets before its torn down on error unwind. nf register net hooks might have published at least one hook; call synchronize rcu() if there was an error.
audit log register message gets deferred until all operations have passed, this avoids need to emit another ureg message in case of error unwinding.
Based on earlier patch by Tristan Madani.
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Related Identifiers

CVE-2026-64079

Affected Products

Linux