CVE-2026-40023

CWE-116CWE-1178 documents6 sources
Severity
6.3MEDIUM
EPSS
0.1%
top 69.19%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Apache Software Foundation Apache Log4cxxApache Software Foundation Apache Log4cxx (brew)Apache Software Foundation Apache Log4cxx (conan)
Timeline
PublishedApr 10
Latest updateApr 13

Description

Apache Log4cxx's XMLLayout https://logging.apache.org/log4cxx/1.7.0/classlog4cxx_1_1xml_1_1XMLLayout.html , in versions before 1.7.0, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/#charsets in log messages, NDC, and MDC property keys and values, producing invalid XML output. Conforming XML parsers must reject such documents with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records. An attacker …

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

Affected Packages3 packages

🔴Vulnerability Details

3
VulDB
Apache Log4cxx up to 1.6.x escape output (Nessus ID 306018)↗2026-04-11
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GHSA
GHSA-q8qr-wp2r-738r: Apache Log4cxx's XMLLayout https://logging↗2026-04-10
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CVEList
Apache Log4cxx, Apache Log4cxx (Conan), Apache Log4cxx (Brew): Silent log event loss in XMLLayout due to unescaped XML 1.0 forbidden characters↗2026-04-10
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📋Vendor Advisories

1
Red Hat
Apache Log4cxx: Apache Log4cxx: Log processing impairment due to unsanitized XML characters↗2026-04-10
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💬Community

3
Bugzilla
CVE-2026-40023 log4cxx: Apache Log4cxx: Log processing impairment due to unsanitized XML characters [epel-all]↗2026-04-13
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Bugzilla
CVE-2026-40023 log4cxx: Apache Log4cxx: Log processing impairment due to unsanitized XML characters [fedora-all]↗2026-04-13
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Bugzilla
CVE-2026-40023 Apache Log4cxx: Apache Log4cxx: Log processing impairment due to unsanitized XML characters↗2026-04-10
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CVE-2026-40023 (MEDIUM CVSS 6.3) | Apache Log4cxx's XMLLayout https:// | cvebase.io