CVE-2026-34477

A flaw was found in Apache Log4j Core. A network-based attacker can perform a man-in-the-middle (MITM) attack, allowing them to intercept encrypted communications. This occurs when an SMTP, Socket, or Syslog appender uses Transport Layer Security (TLS) with a nested <Ssl> element, and the attacker has a certificate from a trusted Certificate Authority (CA). The vulnerability stems from an incomplete hostname verification fix, making TLS connections susceptible to interception.

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 do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.