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Fencer Vulns
low 1.8

CVE-2026-1225 json

Malicious logback.xml configuration file allows instantiation of arbitrary classes

published 2026-01-22 9 mo ago modified 2026-09-10 1 mo ago also GHSA-qqpg-mvqg-649v , EUVD-2026-4130

cvss
1.8
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

ACE vulnerability in configuration file processing by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.

The instantiation of a potentially malicious Java class requires that said class is present on the user's class-path. In addition, the attacker must have write access to a configuration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado.

Patch / fix

  • maven ch.qos.logback:logback-core 1.5.25
  • QOS.CH Sarl Logback-core 1.5.25
  • logback Debian 14 1:1.6.3-1

debian advisories DEBIAN-CVE-2026-1225

  • logback openSUSE Leap 15.6 1.2.13-150200.3.16.1

suse advisories SUSE-SU-2026:0361-1

  • logback openSUSE Tumbleweed 1.2.13-2.1

opensuse advisories openSUSE-SU-2026:10114-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-1225 updated cvss 5.0

ch.qos.logback/logback-core: Malicious logback.xml configuration file allows instantiation of arbitrary classes

  • Red Hat Logging Subsystem for Red Hat OpenShift logback-core Red Hat OpenShift Serverless openshift-serverless-1/kn-ekb-receiver-rhel9, openshift-serverless-1/kn-ekb-dispatcher-rhel9 Red Hat AMQ Broker 7 logback-core Red Hat AMQ Clients logback-core Red Hat build of Apache Camel - HawtIO 4 logback-core Red Hat build of Apache Camel for Spring Boot 4 logback-core
    +5 more products
    Red Hat build of Debezium 2 logback-core Red Hat build of Debezium 3 logback-core Red Hat build of OptaPlanner 8 logback-core Red Hat Data Grid 8 logback-core Red Hat Enterprise Linux 8 log4j, slf4j, log4j-jcl, log4j-web, slf4j-ext, slf4j-jcl, +10 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 9 log4j, slf4j, log4j-jcl, slf4j-jcl, log4j-slf4j, slf4j-jdk14, +7 more
    affected: workaround, no fix available, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 slf4j Red Hat Fuse 7 logback-core Red Hat JBoss Enterprise Application Platform 7 logback-core Red Hat JBoss Enterprise Application Platform 8 logback-core Red Hat JBoss Enterprise Application Platform Expansion Pack logback-core Red Hat JBoss Web Server 6 logback-core
    +6 more products
    Red Hat OpenShift Dev Spaces devspaces/server-rhel9, devspaces/openvsx-rhel9, devspaces/pluginregistry-rhel9 Red Hat Process Automation 7 logback-core Red Hat Satellite 6 candlepin, puppetserver, candlepin-selinux Red Hat Single Sign-On 7 logback-core Red Hat streams for Apache Kafka 2 logback-core Red Hat streams for Apache Kafka 3 logback-core
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 1.8 CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/S:N/AU:N/RE:M/U:Green
CNA 4.0 1.8 CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/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:N/AU:N/R:X/V:X/RE:M/U:Green

Affected packages

ecosystem package affected fixed in
maven ch.qos.logback:logback-core
<1.5.25
1.5.25

Affected products

  • QOS.CH Sarl Logback-core

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.