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 2.138.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1000861 is resolved across your whole dependency graph.

How do I detect CVE-2018-1000861 in my Maven dependencies?

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.

How do I mitigate CVE-2018-1000861 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

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 98.3%, 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 October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

CISA KEV · ACTIVELY EXPLOITED

CRITICAL severity

CVE-2018-1000861 — jenkins-core

CRITICALFix: jenkinsci/jenkins@47f38d7

CVE-2018-1000861 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in org.jenkins-ci.main:jenkins-core. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-02-10) — treat it as actively exploited and patch now. A fix is available for org.jenkins-ci.main:jenkins-core — see the affected versions and patch details below.

Deserialization of Untrusted Data in Jenkins

Also known asGHSA-hhpm-5cp2-hg4x

Published

Dec 10, 2018

Updated

Oct 24, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

6 known

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-02-10. Federal agencies were required to remediate by 2022-08-10.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2018-1000861.

EPSS Exploitation Probability

via FIRST.org ↗

98.3%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2018-1000861 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

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`org.jenkins-ci.main:jenkins-core:2.138.4`
☕Maven	`org.jenkins-ci.main:jenkins-core`	≥ 2.140&&< 2.154	2.154`org.jenkins-ci.main:jenkins-core:2.154`

Affected Products

2 products · 3 configurations

Application

jenkinsjenkins

≤ 2.153

range

Application

openshift container platformredhat

1 version

3.11

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.