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.
| Vendor | Product | Versions |
|---|---|---|
| apache | log4j | maven/org.apache.logging.log4j:log4j-core: >= 2.21.0, < 2.25.4, maven/org.apache.logging.log4j:log4j-core: >= 3.0.0-beta1, <= 3.0.0-beta3 |
Downstream vendors/products affected by this vulnerability
| Vendor | Product | Source | Confidence |
|---|---|---|---|
| apache | log4j | cert_advisory | 90% |
| maven | org.apache.logging.log4j:log4j-core | GHSA | 85% |
Updated severity to HIGH, added new affected version 3.0.0-beta3, and corrected exploit availability status.
Updated affected versions to include 3.0.0-beta2 and 3.0.0-beta3, changed severity to MEDIUM, and marked the vulnerability as actively exploited with an available exploit.
Initial creation
