CVE catalog
CVE-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
- Severity
- Medium · CVSS 6.9
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.97% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | apache-log4j2 | sid | 2.26.1-1 | not affected |
| Debian | apache-log4j2 | forky | 2.19.0-2 | not affected |
| Debian | apache-log4j2 | trixie | 2.19.0-2 | not affected |
| Debian | apache-log4j2 | bookworm | 2.19.0-2 | not affected |
| Debian | apache-log4j1.2 | sid | 1.2.17-11 | not affected |
| Debian | apache-log4j1.2 | forky | 1.2.17-11 | not affected |
| Debian | apache-log4j1.2 | trixie | 1.2.17-11 | not affected |
| Debian | apache-log4j1.2 | bookworm | 1.2.17-11 | not affected |
| Cpe | log4j | Not reported | 2.25.4 | fixed |
| Cpe | log4j | Not reported | Not reported | unknown |
| Cpe | log4j | Not reported | Not reported | unknown |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | apache-log4j2 | source | sid | Not affected | unimportant | Not reported | Not reported |
| Debian | apache-log4j2 | source | forky | Not affected | unimportant | Not reported | Not reported |
| Debian | apache-log4j2 | source | trixie | Not affected | unimportant | Not reported | Not reported |
| Debian | apache-log4j2 | source | bookworm | Not affected | unimportant | Not reported | Not reported |
| Debian | apache-log4j1.2 | source | sid | Not affected | unimportant | Not reported | Not reported |
| Debian | apache-log4j1.2 | source | forky | Not affected | unimportant | Not reported | Not reported |
| Debian | apache-log4j1.2 | source | trixie | Not affected | unimportant | Not reported | Not reported |
| Debian | apache-log4j1.2 | source | bookworm | Not affected | unimportant | Not reported | Not reported |
| Cpe | log4j | cpe | Not reported | 2.25.4 | Not reported | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [liblog4j1.2-java]Not affected
Source package: [apache-log4j1.2]
Details (2)
1.2.17-11· all · bookwormNot affected
nvd · apache-log4j1.2 · debian · bookworm
1.2.17-11· all · bookwormNot affected
nvd · apache-log4j1.2 · debian · bookworm
- [liblog4j1.2-java-doc]Not affected
Source package: [apache-log4j1.2]
Details (2)
1.2.17-11· all · bookwormNot affected
nvd · apache-log4j1.2 · debian · bookworm
1.2.17-11· all · bookwormNot affected
nvd · apache-log4j1.2 · debian · bookworm
- [liblog4j2-java]Not affected
Source package: [apache-log4j2]
Details (2)
2.19.0-2· all · bookwormNot affected
nvd · apache-log4j2 · debian · bookworm
2.19.0-2· all · bookwormNot affected
nvd · apache-log4j2 · debian · bookworm
Observed:
References
- [http://www.openwall.com/lists/oss-security/2026/04/10/7]
- [https://github.com/apache/logging-log4j2/pull/4074]
- [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]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-34478]
- [https://security-tracker.debian.org/tracker/CVE-2026-34478]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34478.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2260.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [Red Hat security advisories and VEX]