Apache Log4j Core: log injection in `Rfc5424Layout` due to silent configuration incompatibility
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.
Software afectado
Haz clic en una tecnología para ver todas sus vulnerabilidades.
| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Java / Kotlin (Maven) | org.apache.logging.log4j:log4j-core | >= 2.21.0, < 2.25.4, >= 3.0.0-beta1, <= 3.0.0-beta3 | 2.25.4 |
Referencias
- https://nvd.nist.gov/vuln/detail/CVE-2026-34478
- https://github.com/apache/logging-log4j2/pull/4074
- https://github.com/apache/logging-log4j2
- https://lists.apache.org/thread/3k1clr2l6vkdnl4cbhjrnt1nyjvb5gwt
- https://logging.apache.org/cyclonedx/vdr.xml
- https://logging.apache.org/log4j/2.x/manual/layouts.html#RFC5424Layout
- https://logging.apache.org/security.html#CVE-2026-34478
- http://www.openwall.com/lists/oss-security/2026/04/10/7
- Vector CVSS
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N- Debilidad (CWE)
CWE-117, CWE-684- Plataforma
- Java / Kotlin (Maven)
- Paquete
org.apache.logging.log4j:log4j-core- Publicada
- 10.04.2026
- Actualizado
- 11.10.2026 13:20
Fuentes y licencias
OSV / GitHub Advisory Database - GHSA-445c-vh5m-36rj - CC BY 4.0
Historial de vulnerabilidades: org.apache.logging.log4j:log4j-core
Todas las vulnerabilidades publicadas de este paquete (Java / Kotlin (Maven)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 11
- Primera → última
- 01.2020 04.2026
- Sin corrección
- 0
- Explotada en ataques
- 2
Distribución por gravedad
- Crítica 3
- Alta 2
- Media 5
- Baja 1
Divulgaciones por año
- 2020: 2
- 2021: 3
- 2022: 1
- 2023: 1
- 2024: 0
- 2025: 1
- 2026: 3
-
Apache Log4j Core: log injection in `Rfc5424Layout` due to silent configuration incompatibility esta entrada
Identifica las vulnerabilidades de tu aplicación
Con la integración de DockRay y el inventario de software activado, DockRay compara las versiones notificadas de los componentes con las vulnerabilidades conocidas y avisa de las coincidencias confirmadas. La cobertura depende de la tecnología compatible y de los avisos disponibles.