SB2026062436 - Multiple vulnerabilities in IBM License Metric Tool

Security Bulletin ID SB2026062436

CSH Severity

Medium

Patch available

YES

Number of vulnerabilities 11

Exploitation vector Remote access

Highest impact Information disclosure

Breakdown by Severity

Low
Medium
High
Critical

Description

This security bulletin contains information about 11 vulnerabilities.

1) Improper Certificate Validation (CVE-ID: CVE-2026-34477)

CWE-ID: CWE-295 - Improper Certificate Validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to perform a man-in-the-middle attack.

The vulnerability exists due to improper certificate validation in the TLS hostname verification handling of the verifyHostName attribute in Log4j Core SSL configuration when establishing TLS connections for SMTP, Socket, or Syslog appenders. A remote attacker can present a certificate issued by a trusted certificate authority to perform a man-in-the-middle attack.

The issue occurs only when TLS is configured via a nested SSL configuration element, and it does not affect the HTTP appender.

2) Improper validation of certificate with host mismatch (CVE-ID: CVE-2025-68161)

CWE-ID: CWE-297 - Improper Validation of Certificate with Host Mismatch

CVSSv4: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:L/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to the Socket Appender does not perform TLS hostname verification of the peer certificate, even when the "verifyHostName" configuration attribute or the "log4j2.sslVerifyHostName" system property is set to true. A remote attacker can perform MitM attack and intercept or redirect the log traffic.

3) Improper Output Neutralization for Logs (CVE-ID: CVE-2026-34478)

CWE-ID: CWE-117 - Improper Output Neutralization for Logs

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to inject arbitrary log entries.

The vulnerability exists due to improper neutralization of CRLF sequences in Rfc5424Layout when processing logged data with direct Rfc5424Layout configuration using TCP framing. A remote attacker can supply specially crafted input containing CRLF sequences to inject arbitrary log entries.

Only users of stream-based syslog services who configure Rfc5424Layout directly are affected. Users of the SyslogAppender are not affected.

4) Improper Encoding or Escaping of Output (CVE-ID: CVE-2026-34480)

CWE-ID: CWE-116 - Improper Encoding or Escaping of Output

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause log event loss.

The vulnerability exists due to improper output neutralization in XmlLayout when processing log messages or MDC values containing XML 1.0 forbidden characters. A remote attacker can supply crafted input containing forbidden characters to cause log event loss.

The impact depends on the StAX implementation in use: built-in JRE StAX may produce malformed XML that downstream parsers reject, while alternative implementations may throw an exception during the logging call so the event is delivered only to Log4j's internal status logger.

5) Improper input validation (CVE-ID: CVE-2026-22016)