CVE-2026-56123

A flaw was found in socat. A remote attacker, acting as a malicious SOCKS5 proxy server, can exploit a heap-based buffer overflow. This vulnerability, caused by a sign-extension flaw in the DOMAINNAME reply parser, allows the attacker to write arbitrary data to memory. This could lead to arbitrary code execution or a denial of service.

This issue affected socat versions 1.8.0.0 - 1.8.1.1. Red Hat Enterprise Linux 7, 8, 9, and 10 include older socat 1.7.* versions and are therefore not affected by this issue.

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.