CVE-2025-59476 — jenkins-core
MEDIUMCVE-2025-59476 is a medium-severity (CVSS 5.3) CWE-117 vulnerability in org.jenkins-ci.main:jenkins-core. A fix is available for org.jenkins-ci.main:jenkins-core — see the affected versions and patch details below.
Jenkins has a log message injection vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-59476.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.jenkins-ci.main:jenkins-core☕org.jenkins-ci.main:jenkins-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
In Jenkins 2.527 and earlier, LTS 2.516.2 and earlier, the log formatter that prepares log messages for console output (including jenkins.log and equivalent) does not restrict or transform the characters that can be inserted from user-specified content in log messages.
This allows attackers able to control log message contents to insert line break characters, followed by forged log messages that may mislead administrators reviewing log output.
Jenkins 2.528, LTS 2.516.3 adds an indicator at the beginning of a line that was inserted as part of log message content: [CR], [LF], or [CRLF] (representing the kind of line break), followed by > .
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.jenkins-ci.main:jenkins-core | all versions | 2.516.3org.jenkins-ci.main:jenkins-core:2.516.3 |
| ☕Maven | org.jenkins-ci.main:jenkins-core | ≥ 2.517&&< 2.528 | 2.528org.jenkins-ci.main:jenkins-core:2.528 |
Affected Products
jenkinsjenkinsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.main:jenkins-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.jenkins-ci.main:jenkins-core to 2.516.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59476 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for CVE-2025-59476 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2025-59476 in your dependencies?
Find it across Maven, including transitive dependencies.