Service unavailability via abandoned worker threads
Published Jan 7, 2026 · Updated Jan 7, 2026
Denial of service in affected Quarkus REST releases allows remote attackers to exhaust worker threads by dropping HTTP connections. The response-writing path waits for earlier chunks to be fully transmitted but never releases its worker thread if the client disconnects during that wait. Repeated unauthenticated requests and precisely timed disconnects can permanently consume the pool, degrading responses or making the application unavailable.
Summary
What happened
Denial of service in affected Quarkus REST releases allows remote attackers to exhaust worker threads by dropping HTTP connections. The response-writing path waits for earlier chunks to be fully transmitted but never releases its worker thread if the client disconnects during that wait. Repeated unauthenticated requests and precisely timed disconnects can permanently consume the pool, degrading responses or making the application unavailable.
The record
- CVE
- CVE-2025-66560
- Published
- Jan 7, 2026
- Updated
- Jan 7, 2026
- Vendor
- Quarkus
- Product
- Quarkus
- Classifications
- CWE-770, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 7, 2026CVE publishedPublication date reported by the CVE source.
- Jan 7, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.20.5
- Affected versionversion=>= 3.21.0, < 3.27.2
- Affected versionversion=>= 3.30.0, < 3.31.0
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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