CVE-2026-27100 is a medium-severity (CVSS 4.3) Information Exposure 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 build information disclosure vulnerability through Run Parameter
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-2026-27100.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-27100 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 2.550 and earlier, LTS 2.541.1 and earlier accepts Run Parameter values that refer to builds the user submitting the build does not have access to, allowing attackers with Item/Build and Item/Configure permission to obtain information about the existence of jobs, the existence of builds, and if a specified build exists, its display name.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.jenkins-ci.main:jenkins-core | ≥ 2.542&&< 2.551 | 2.551org.jenkins-ci.main:jenkins-core:2.551 |
| ☕Maven | org.jenkins-ci.main:jenkins-core | all versions | 2.541.2org.jenkins-ci.main:jenkins-core:2.541.2 |
Detection & 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 2.551 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27100 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-27100 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-27100. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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 information disclosure vulnerability in Jenkins allows an attacker with Item/Build and Item/Configure permissions to gain knowledge about the existence and display names of jobs and builds they are not authorized to access. This affects Jenkins instances in OpenShift Developer Tools & Services.
| Product | Fixed in | Advisory |
|---|---|---|
| OpenShift Developer Tools and Services 4.12 | ocp-tools-4/jenkins-rhel8:1776764096 | RHSA-2026:10209 |
| OpenShift Developer Tools and Services 4.13 | ocp-tools-4/jenkins-rhel8:1776764096 | RHSA-2026:10201 |
| OpenShift Developer Tools and Services 4.14 | ocp-tools-4/jenkins-rhel8:1776762347 | RHSA-2026:10211 |
| OpenShift Developer Tools and Services 4.15 | ocp-tools-4/jenkins-rhel8:1776762347 | RHSA-2026:10204 |
| OpenShift Developer Tools and Services 4.16 | ocp-tools-4/jenkins-rhel9:1776944215 | RHSA-2026:10214 |
| OpenShift Developer Tools and Services 4.17 | ocp-tools-4/jenkins-rhel9:1776944215 | RHSA-2026:10213 |
| OpenShift Developer Tools and Services 4.18 | ocp-tools-4/jenkins-rhel9:1776944215 | RHSA-2026:10215 |
| OpenShift Developer Tools and Services 4.19 | ocp-tools-4/jenkins-rhel9:1776944215 | RHSA-2026:10206 |
Frequently Asked Questions
Is CVE-2026-27100 in your dependencies?
O3 Security finds CVE-2026-27100 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.