Vulnerability GHSA-445c-vh5m-36rj
Medium Risk
MEDIUM RISK
CVSS Score: 6.0
Score Range: 4.0–6.9
Medium severity vulnerabilities (CVSS 4.0–6.9). Important issues that meaningfully reduce security confidence.
5 months ago
April 10, 2026 at 06:31 PM UTC
Apache Log4j Core: log injection in `Rfc5424Layout` due to silent configuration incompatibility
2.21.0 - 3.0.0
2.21.0 - 3.0.0
Summary
Apache Log4j Core: log injection in `Rfc5424Layout` due to silent configuration incompatibility
Details
Apache Log4j Core's 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
newLineEscapeattribute 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
useTlsMessageFormatattribute 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.
Related Vulnerabilities
Other vulnerabilities affecting the same packages
Medium Risk
5 months ago
Apache Log4j Core: Silent log event loss in XmlLayout due to unescaped XML 1.0 forbidden characters
2.1.0 - 2.2.0 and 2.4.0 - 2.5.0 and 2.7.0 and 2.9.0 - 2.10.0 and 2.14.0 - 2.16.0 and 2.18.0 - 3.0.0 GHSA-3pxv-7cmr-fjr4
2.1.0 - 2.2.0 and 2.4.0 - 2.5.0 and 2.7.0 and 2.9.0 - 2.10.0 and 2.14.0 - 2.16.0 and 2.18.0 - 3.0.0 GHSA-3pxv-7cmr-fjr4
Medium Risk
5 months ago
Apache Log4j Core: `verifyHostName` attribute silently ignored in TLS configuration
2.14.0 - 2.16.0 and 2.18.0 - 3.0.0 GHSA-6hg6-v5c8-fphq
2.14.0 - 2.16.0 and 2.18.0 - 3.0.0 GHSA-6hg6-v5c8-fphq
Medium Risk
9 months ago
Apache Log4j does not verify the TLS hostname in its Socket Appender
2.1.0 - 2.2.0 and 2.4.0 - 2.5.0 and 2.7.0 and 2.9.0 - 2.10.0 and 2.14.0 - 2.16.0 and 2.18.0 - 2.23.1 GHSA-vc5p-v9hr-52mj
2.1.0 - 2.2.0 and 2.4.0 - 2.5.0 and 2.7.0 and 2.9.0 - 2.10.0 and 2.14.0 - 2.16.0 and 2.18.0 - 2.23.1 GHSA-vc5p-v9hr-52mj
High Risk
3 years ago
Apache Log4j 1.x (EOL) allows Denial of Service (DoS)
==2.0-alpha1, ==2.0-alpha2, ==2.0-beta1, ==2.0-beta2, ==2.0-beta3, ==2.0-beta4, ==2.0-beta5, ==2.0-beta6, ==2.0-beta7, ==2.0-beta8, ==2.0-beta9, ==2.0-rc1, ==2.0-rc2 GHSA-vp98-w2p3-mv35
==2.0-alpha1, ==2.0-alpha2, ==2.0-beta1, ==2.0-beta2, ==2.0-beta3, ==2.0-beta4, ==2.0-beta5, ==2.0-beta6, ==2.0-beta7, ==2.0-beta8, ==2.0-beta9, ==2.0-rc1, ==2.0-rc2 GHSA-vp98-w2p3-mv35
Medium Risk
4 years ago
Improper Input Validation and Injection in Apache Log4j2
2.1.0 - 2.5.0 and 2.7.0 and 2.9.0 - 2.10.0 and 2.14.0 - 2.17.0 GHSA-8489-44mv-ggj8
2.1.0 - 2.5.0 and 2.7.0 and 2.9.0 - 2.10.0 and 2.14.0 - 2.17.0 GHSA-8489-44mv-ggj8
Impacted packages
Timeline
Published
5 months ago
April 10, 2026 at 06:31 PM UTC
Fixed (2.25.4)
Unknown
Unknown
Last Modified
22 days ago
September 10, 2026 at 03:50 AM UTC