CVE Explorer
CVE-2026-34479
The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records.
Two groups of users are affected:
* Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file.
* Those using the Log4j 1 con
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"collectionURL":"https://repo.maven.apache.org/maven2","cpes":["cpe:2.3:a:apache:log4j_1_2_api:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","packageName":"org.apache.logging.log4j:log4j-1.2-api","packageURL":"pkg:maven/org.apache.logging.log4j/log4j-1.2-api","product":"Apache Log4j 1 to Log4j 2 bridge","vendor":"Apache Software Foundation","versions":[{"lessThan":"2.25.4","status":"affected","version":"2.7","versionType":"maven"},{"lessThanOrEqual":"3.0.0-beta2","status":"affected","version":"3.0.0-alpha1","versionType":"maven"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":6.9,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"LOW","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NO…
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/metrics/0/cvssV4_0
CWE assertions
1 source assertion{"cweId":"CWE-116","description":"CWE-116 Improper Encoding or Escaping of Output","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/problemTypes/0/descriptions/0
Source references
6 source assertions{"url":"http://www.openwall.com/lists/oss-security/2026/04/10/8"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/adp/0/references/0
{"tags":["patch"],"url":"https://github.com/apache/logging-log4j2/pull/4078"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/references/0
{"tags":["vendor-advisory"],"url":"https://lists.apache.org/thread/gd0hp6mj17rn3kj279vgy4p7kd4zz5on"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/references/4
{"tags":["vendor-advisory"],"url":"https://logging.apache.org/cyclonedx/vdr.xml"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/references/2
{"tags":["related"],"url":"https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/references/3
{"tags":["vendor-advisory"],"url":"https://logging.apache.org/security.html#CVE-2026-34479"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8c284ea6fa7a919e17a2a6cd5b194eaabbbc4b443a6eeabbc7e7812f4d01a6a7 · sha256:d8a1f46550ec59d6… · /containers/cna/references/1
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.