CVE-2026-74624netfilter: nf_conntrack: defer invalid log until after unlock

Official 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.

Affected packages & fixed versions

Affected products (as reported)

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