CVE-2026-53269

A flaw was found in the Linux kernel's netfilter synproxy component. This vulnerability is caused by a race condition during the on-demand registration of netfilter hooks. A local user with privileges to modify netfilter rules could exploit this flaw by concurrently adding iptables targets or nftables expressions. This could lead to unexpected behavior or system instability, potentially resulting in a denial of service (DoS).

This vulnerability is rated with a Moderate severity impact because exploitation requires local access with administrative capabilities to configure firewall rules, or the ability to create unprivileged user namespaces, limiting the attack surface to authenticated users. Under default Red Hat Enterprise Linux configurations, SYNPROXY targets and expressions are not enabled, meaning an attacker must specifically induce racing rule installations to provoke hook registration inconsistencies. Successful exploitation could trigger a kernel panic or system lockup, resulting in a denial of service without exposing confidential data or permitting unauthorized privileges.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.