Connect your agent
AdvisoriesCriticalCheck your lockfilePluginHow it worksPricing Connect your agent

Advisory record · GHSA-445c-vh5m-36rj

Apache Log4j Core: log injection in `Rfc5424Layout` due to silent configuration incompatibility

CVSS 6.9 MediumEPSS 0.0097 · 62nd percentile

Published by the GitHub Advisory Database at 10 Apr 2026, 18:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
org.apache.logging.log4j:log4j-coreMaven>=2.21.0, <2.25.4 || >=3.0.0-beta1, <=3.0.0-beta32.25.4
Identifiers
GHSA-445c-vh5m-36rj · CVE-2026-34478
Weakness (CWE)
CWE-117 · CWE-684
Tags
Published
10 Apr 2026
Updated
10 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Apache Log4j Core versions 2.21.0 through 2.25.3 (and 3.0.0-beta1 through 3.0.0-beta3) are vulnerable to log injection via CRLF sequences in Rfc5424Layout when it is configured directly for stream-based syslog. Two attribute renames silently disabled newline escaping for TCP (RFC 6587) and downgraded TLS (RFC 5425) users to unescaped TCP; SyslogAppender is not affected. Upgrade to Apache Log4j Core 2.25.4.

Written 2 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
6.9 Medium 4.0 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 CNA (apache)
  • CISA KEV Not listed.
  • EPSS 0.0097, the 62nd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:17 UTC First seen by agentprime
  2. 31 Oct 2026, 14:17 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.