ANCHORE-2026-34478
Apache Log4j Core's Rfc5424Layout https://logging.apache.org/log4j/2.x/manual/layouts.html#RFC5424Layout , in versions 2.21.0 through 2.25.3, is vulnerable to log injection via CRLF sequences due to undocumented renames of security-relevant configuration attributes. Two distinct issues affect users of stream-based syslog services who configure Rfc5424Layout directly: * The newLineEscape attribute was silently renamed, causing newline escaping to stop working for users of TCP framing (RFC 6587), exposing them to CRLF injection in log output. * The useTlsMessageFormat attribute was silently renamed, causing users of TLS framing (RFC 5425) to be silently downgraded to unframed TCP (RFC 6587), without newline escaping. Users of the SyslogAppender are not affected, as its configuration attributes were not modified. Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Log4j Core | 2.21.0, 3.0.0-beta1 |
Timeline
- Apr 10, 2026 CVE Published
- Apr 10, 2026 CVE Updated
References
- https://github.com/apache/logging-log4j2/pull/4074 url
- https://lists.apache.org/thread/3k1clr2l6vkdnl4cbhjrnt1nyjvb5gwt url
- https://logging.apache.org/cyclonedx/vdr.xml url
- https://logging.apache.org/log4j/2.x/manual/layouts.html#RFC5424Layout url
- https://logging.apache.org/security.html#CVE-2026-34478 url