Unauthenticated controller hang via stranded CLI threads
Published Dec 10, 2025 · Updated Dec 16, 2025
Denial of service in Jenkins 2.540 and earlier and LTS 2.528.2 and earlier allows remote attackers to hang controllers via HTTP CLI. The plain /cli?remoting=false endpoint pairs two POST streams in an unsynchronized session map, while handshake and upload wait loops lack deadlines and fail to close corrupted streams. No authentication is required; abandoned or mispaired sessions strand Jetty request threads indefinitely until controller service is exhausted.
Summary
What happened
Denial of service in Jenkins 2.540 and earlier and LTS 2.528.2 and earlier allows remote attackers to hang controllers via HTTP CLI. The plain /cli?remoting=false endpoint pairs two POST streams in an unsynchronized session map, while handshake and upload wait loops lack deadlines and fail to close corrupted streams. No authentication is required; abandoned or mispaired sessions strand Jetty request threads indefinitely until controller service is exhausted.
The record
- CVE
- CVE-2025-67635
- Published
- Dec 10, 2025
- Updated
- Dec 16, 2025
- Vendor
- Jenkins Project
- Product
- Jenkins
- Classifications
- CWE-404, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 10, 2025CVE publishedPublication date reported by the CVE source.
- Dec 16, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- racecond_a.py HashMap race proof of conceptproof of concept · demonstrated
- racecond_b.py protocol-abandonment proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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