How severe is CVE-2018-1000861?

CVE-2018-1000861 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2018-1000861?

CVE-2018-1000861 affects the following packages: org.jenkins-ci.main:jenkins-core (Maven), org.jenkins-ci.main:jenkins-core (Maven). Ecosystems affected: Maven.

How do I fix CVE-2018-1000861?

Update org.jenkins-ci.main:jenkins-core to version 2.138.4 or later. Run your dependency manager's update command and verify no transitive dependencies pin the vulnerable version. Use O3 Security's SCA scanner to confirm the fix is applied across your entire dependency tree.

Is CVE-2018-1000861 actively exploited in the wild?

Yes. There are 6 known exploit references for CVE-2018-1000861, including 5 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2018-1000861?

CVE-2018-1000861 has an EPSS (Exploit Prediction Scoring System) score of 94.5%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2018-1000861 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2018-1000861 (Jenkins Stapler Web Framework Deserialization of Untrusted Data Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2022-02-10. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-08-10. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2018-1000861?

CVE-2018-1000861 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2018-1000861?

A Nuclei detection template exists for CVE-2018-1000861, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2018-1000861 published, and has it been updated?

CVE-2018-1000861 was published on December 10, 2018 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2022-02-10 — agencies required to remediate by 2022-08-10

☕ Maven

CVE-2018-1000861

CRITICAL

Deserialization of Untrusted Data in Jenkins

Also known asGHSA-hhpm-5cp2-hg4x

Published

Dec 10, 2018

Updated

Apr 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

6 known

EPSS Exploitation Probability

via FIRST.org ↗

94.5%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

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.

Blast Radius

2 pkgs affected

☕org.jenkins-ci.main:jenkins-core☕org.jenkins-ci.main:jenkins-core

Real-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

A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153 and earlier, LTS 2.138.3 and earlier in stapler/core/src/main/java/org/kohsuke/stapler/MetaClass.java that allows attackers to invoke some methods on Java objects by accessing crafted URLs that were not intended to be invoked this way.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.jenkins-ci.main:jenkins-core`	all versions	2.138.4
☕Maven	`org.jenkins-ci.main:jenkins-core`	≥ 2.140&&< 2.154	2.154

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.