CVE-2026-40023 | BDVDB-2026-326375 Detail
ApacheApache Log4cxx
Description#
Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx_1_1xml_1_1XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/#charsets in log messages, NDC, and MDC property keys and values, producing invalid XML output. Conforming XML parsers must reject such documents with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records. An attacker who can influence logged data can exploit this to suppress individual log records, impairing audit trails and detection of malicious activity. Users are advised to upgrade to Apache Log4cxx 1.7.0, which fixes this issue.
Impact#
Per CVSS v4.0: confidentiality impact none, integrity impact none, availability impact none. Attack vector: network.
Weaknesses#
- CWE-116 Improper Encoding or Escaping of Output
References#
- https://github.com/apache/logging-log4cxx/pull/609
- https://logging.apache.org/security.html#CVE-2026-40023
- https://logging.apache.org/cyclonedx/vdr.xml
- https://logging.apache.org/log4cxx/1.7.0/classlog4cxx_1_1xml_1_1XMLLayout.html
- https://lists.apache.org/thread/y15cv3zblg3dfwr5vy6ddbnl4zyrzr8b
- http://www.openwall.com/lists/oss-security/2026/04/10/12
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.