CVE-2026-43233

A flaw was found in the Linux kernel's nf_conntrack_h323 helper. A remote attacker could exploit this by sending a specially crafted Q.931 SETUP message to port 1720 through a firewall with the nf_conntrack_h323 helper active. This memory corruption vulnerability leads to an out-of-bounds read, which can result in a heap-buffer-overflow.

This vulnerability is rated Moderate because the out-of-bounds access is restricted to a minor heap over-read of one or two bytes, primarily posing a risk of system crash and denial of service rather than code execution. Red Hat Enterprise Linux does not load or enable the nf_conntrack_h323 netfilter helper by default, limiting exposure to systems explicitly configured to inspect H.323 network traffic. Deployments without active H.323 connection tracking rules are not exposed to this flaw.

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.