GHSA-26wc-3wqp-g3rp
CRITICALGHSA-26wc-3wqp-g3rp is a critical-severity (CVSS 9.8) remote code execution vulnerability in org.jenkins-ci.main:jenkins-core. It is in CISA's Known Exploited Vulnerabilities catalog (added 2025-10-02) — treat it as actively exploited and patch now. O3 Security confirms whether GHSA-26wc-3wqp-g3rp is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Deserialization of Untrusted Data in Jenkins
Blast Radius
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 versions 2.56 and earlier as well as 2.46.1 LTS and earlier are vulnerable to an unauthenticated remote code execution. An unauthenticated remote code execution vulnerability allowed attackers to transfer a serialized Java SignedObject object to the Jenkins CLI, that would be deserialized using a new ObjectInputStream, bypassing the existing blacklist-based protection mechanism. We're fixing this issue by adding SignedObject to the blacklist. We're also backporting the new HTTP CLI protocol from Jenkins 2.54 to LTS 2.46.2, and deprecating the remoting-based (i.e. Java serialization) CLI protocol, disabling it by default.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.jenkins-ci.main:jenkins-core | ≥ 2.50&&< 2.57 | 2.57 |
| ☕Maven | org.jenkins-ci.main:jenkins-core | all versions | 2.46.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
CloudBees Jenkins 2.32.1 - Java Deserialization
by SecuriTeam · May 5, 2017
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.jenkins-ci.main:jenkins-core to 2.57 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-26wc-3wqp-g3rp 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 pinpoints whether GHSA-26wc-3wqp-g3rp is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-26wc-3wqp-g3rp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-26wc-3wqp-g3rp in your dependencies?
O3 detects GHSA-26wc-3wqp-g3rp across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.