CVE-2026-74624
Received Received - Intake

Invalid Log Deadlock in Linux Kernel Netfilter

Vulnerability report for CVE-2026-74624, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-22

Last updated on: 2026-08-22

Assigner: kernel.org

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.

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Meta Information

Published
2026-08-22
Last Modified
2026-08-22
Generated
2026-08-22
AI Q&A
2026-08-22
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a deadlock risk in the netfilter connection tracking system. When handling invalid TCP or SCTP packets, the system logs errors while holding a lock (ct->lock). If logging is routed to nfnetlink_log with conntrack export enabled, it can re-enter the netlink glue code, attempt to dump the same connection tracking entry, and try to acquire the same lock again, causing a deadlock.

Impact Analysis

This vulnerability can cause system hangs or crashes due to deadlocks in the Linux kernel's networking stack. If exploited, it may lead to denial-of-service conditions, disrupting network services and connectivity on affected systems.

Mitigation Strategies

Update the Linux kernel to the latest stable version that includes the fix for CVE-2026-74624. Monitor kernel security advisories for patches and apply them promptly.

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