CVE catalog
CVE-2026-40023
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 specificat
- Severity
- Medium · CVSS 6.3
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/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
- 0.50% · Oct 25, 2026
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 who can influence logged data can exploit this to suppress individual log records, impairing audit trails and detection of malicious activity. Users are advised to upgrade to Apache Log4cxx 1.7.0, which fixes 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 | log4cxx | sid | 1.5.0-1 | vulnerable |
| Debian | log4cxx | forky | 1.5.0-1 | vulnerable |
| Debian | log4cxx | trixie | 1.4.0-1+deb13u1 | vulnerable |
| Debian | log4cxx | bookworm | 1.0.0-1+deb12u1 | vulnerable |
| Cpe | log4cxx | Not reported | Not reported | vulnerable |
| Cpe | log4cxx | Not reported | 1.7.0 | fixed |
| Opensuse | log4cxx | tumbleweed | 1.7.0-2.1 | fixed |
| Cpe | log4cxx | Not reported | 1.7.0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | log4cxx | source | sid | (unfixed) | not yet assigned | Not reported | [1133368] |
| Debian | log4cxx | source | forky | (unfixed) | not yet assigned | Not reported | [1133368] |
| Debian | log4cxx | source | trixie | (unfixed) | not yet assigned | Not reported | [1133368] |
| Debian | log4cxx | source | bookworm | (unfixed) | not yet assigned | Not reported | [1133368] |
| Cpe | log4cxx | cpe | Not reported | 1.7.0 | Not reported | Not reported | Not reported |
| Opensuse | log4cxx | rpm | tumbleweed | 1.7.0-2.1 | Not reported | OPENSUSE-SU-2026:10566-1 | Not reported |
| Cpe | log4cxx | cpe | Not reported | 1.7.0 | Not reported | NVD-CVE-2026-40023 | Not reported |
Notes
[trixie] log4cxx: Minor issue [bookworm] log4cxx: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [liblog4cxx15]Affected
Source package: [log4cxx]
Details (2)
1.0.0-1+deb12u1· amd64 · bookwormAffected
nvd · log4cxx · debian · bookworm; nvd · log4cxx · debian · 12
1.0.0-1+deb12u1· arm64 · bookwormAffected
nvd · log4cxx · debian · bookworm; nvd · log4cxx · debian · 12
- [liblog4cxx-dev]Affected
Source package: [log4cxx]
Details (2)
1.0.0-1+deb12u1· amd64 · bookwormAffected
nvd · log4cxx · debian · bookworm; nvd · log4cxx · debian · 12
1.0.0-1+deb12u1· arm64 · bookwormAffected
nvd · log4cxx · debian · bookworm; nvd · log4cxx · debian · 12
- [liblog4cxx-doc]Affected
Source package: [log4cxx]
Details (2)
1.0.0-1+deb12u1· all · bookwormAffected
nvd · log4cxx · debian · bookworm; nvd · log4cxx · debian · 12
1.0.0-1+deb12u1· all · bookwormAffected
nvd · log4cxx · debian · bookworm; nvd · log4cxx · debian · 12
[Debian 13 (Trixie)]
- [liblog4cxx15]Affected
Source package: [log4cxx]
Details (2)
1.4.0-1+deb13u1· amd64 · trixieAffected
nvd · log4cxx · debian · 13
1.4.0-1+deb13u1· arm64 · trixieAffected
nvd · log4cxx · debian · 13
- [liblog4cxx-dev]Affected
Source package: [log4cxx]
Details (2)
1.4.0-1+deb13u1· amd64 · trixieAffected
nvd · log4cxx · debian · 13
1.4.0-1+deb13u1· arm64 · trixieAffected
nvd · log4cxx · debian · 13
- [liblog4cxx-doc]Affected
Source package: [log4cxx]
Details (2)
1.4.0-1+deb13u1· all · trixieAffected
nvd · log4cxx · debian · 13
1.4.0-1+deb13u1· all · trixieAffected
nvd · log4cxx · debian · 13
[openSUSE Tumbleweed]
- [liblog4cxx15]Unknown
Source package: [log4cxx]
Details (1)
1.8.0-1.1· x86_64 · tumbleweedUnknown · Fixed:
1.7.0-2.1Version impact unknown
nvd · log4cxx · opensuse · tumbleweed
- [liblog4cxx-devel]Unknown
Source package: [log4cxx]
Details (1)
1.8.0-1.1· x86_64 · tumbleweedUnknown · Fixed:
1.7.0-2.1Version impact unknown
nvd · log4cxx · opensuse · tumbleweed
Observed:
References
- [http://www.openwall.com/lists/oss-security/2026/04/10/12]
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_10566-1.json]
- [https://github.com/apache/logging-log4cxx/pull/609]
- [https://lists.apache.org/thread/y15cv3zblg3dfwr5vy6ddbnl4zyrzr8b]
- [https://logging.apache.org/cyclonedx/vdr.xml]
- [https://logging.apache.org/log4cxx/1.7.0/classlog4cxx_1_1xml_1_1XMLLayout.html]
- [https://logging.apache.org/security.html#CVE-2026-40023]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-40023]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-40023]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:10566-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-40023]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40023.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2292.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]