What is CVE-2018-1000861?

CVE-2018-1000861 is a critical-severity vulnerability in Jenkins, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2018-12-10.

How severe is CVE-2018-1000861?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2018-1000861 known to be exploited?

Yes. CVE-2018-1000861 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-02-10), indicating it is being actively exploited. 89 public proof-of-concept repositories are indexed.

Deserialization in Jenkins

CVE-2018-1000861

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.

Vulnerability class: Insecure Deserialization

Published 2018-12-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.983 (99.9th percentile), scored 2026-10-15.

Very high probability of exploitation in the next 30 days — among the top 0.1% most-likely-to-be-exploited CVEs. 100th percentile — 99.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.983 · newest: 0.983 · change: 0.000

Affected products

Jenkins
Red Hat Openshift Container Platform — versions 3.11

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2022-02-10. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-08-10.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

jenkins.io/security/advisory/2018-12-05/ (Vendor Advisory)
access.redhat.com/errata/RHBA-2019:0024 (vendor-advisory, Third Party Advisory)
www.securityfocus.com/bid/106176 (vdb-entry, Broken Link)
packetstormsecurity.com/files/166778/Jenkins-Remote-Code-Execution.html (VDB Entry, Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2018-1000861?: CVE-2018-1000861 is a critical-severity vulnerability in Jenkins, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2018-12-10.
How severe is CVE-2018-1000861?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2018-1000861 known to be exploited?: Yes. CVE-2018-1000861 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-02-10), indicating it is being actively exploited. 89 public proof-of-concept repositories are indexed.