CVE-2026-53269: netfilter: synproxy: add mutex to guard hook reference counting
In the Linux kernel, the following vulnerability has been resolved:
netfilter: synproxy: add mutex to guard hook reference counting
As the synproxy infrastructure register netfilter hooks on-demand when a user adds the first iptables target or nftables expression, if done concurrently they can race each other.
Introduce a mutex to serialize the refcount control blocks access from both frontends. While a per namespace mutex might be more efficient, it is not needed for target/expression like SYNPROXY.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.143.1-1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-53269?
The severity of CVE-2026-53269 is rated at 34.
How do I fix CVE-2026-53269?
To fix CVE-2026-53269, update your Linux kernel to the latest version that includes the necessary patches for netfilter and synproxy.
What components are affected by CVE-2026-53269?
CVE-2026-53269 affects the Linux kernel's netfilter subsystem related to synproxy.
What type of vulnerability is CVE-2026-53269?
CVE-2026-53269 is a race condition vulnerability involving mutexes in hook reference counting.
When was CVE-2026-53269 published?
CVE-2026-53269 was published on June 25, 2026.