CVE-2026-53437 is a medium-severity (CVSS 4.3) Open Redirect 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 Open Redirect Through Newline/Tab Characters in Redirect URL
Exploitation Status
No confirmed exploitation observed yet
- 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-2026-53437.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-53437 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 380,066 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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
Jenkins 2.567 and earlier, LTS 2.555.2 and earlier improperly determines that a redirect URL after login is legitimately pointing to Jenkins when it contains tab or newline characters between //, allowing attackers to perform phishing attacks.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.jenkins-ci.main:jenkins-core | all versions | 2.555.3org.jenkins-ci.main:jenkins-core:2.555.3 |
| ☕Maven | org.jenkins-ci.main:jenkins-core | ≥ 2.556&&< 2.568 | 2.568org.jenkins-ci.main:jenkins-core:2.568 |
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 2.555.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53437 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.
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.
This is an Important vulnerability in Jenkins that allows remote attackers to conduct phishing attacks. The flaw stems from improper validation of redirect URLs after login, specifically when tab or newline characters are present, which can be exploited to redirect users to malicious sites. This could lead to…
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-2026-53437 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| OpenShift Developer Tools and Services 4.12 | ocp-tools-4/jenkins-rhel8:1786628667 | RHSA-2026:60247 |
| OpenShift Developer Tools and Services 4.13 | ocp-tools-4/jenkins-rhel8:1786628681 | RHSA-2026:60249 |
| OpenShift Developer Tools and Services 4.14 | ocp-tools-4/jenkins-rhel8:1786533561 | RHSA-2026:60248 |
| OpenShift Developer Tools and Services 4.15 | ocp-tools-4/jenkins-rhel8:1786533565 | RHSA-2026:60239 |
| OpenShift Developer Tools and Services 4.16 | ocp-tools-4/jenkins-rhel9:1787125166 | RHSA-2026:60251 |
| OpenShift Developer Tools and Services 4.17 | ocp-tools-4/jenkins-rhel9:1787124635 | RHSA-2026:60246 |
| OpenShift Developer Tools and Services 4.18 | ocp-tools-4/jenkins-rhel9:1787125069 | RHSA-2026:60250 |
| OpenShift Developer Tools and Services 4.19 | ocp-tools-4/jenkins-rhel9:1787124632 | RHSA-2026:60252 |
Frequently Asked Questions
Is CVE-2026-53437 in your dependencies?
Find it across Maven, including transitive dependencies.