CVE-2025-66560
Quarkus is a Cloud Native, (Linux) Container First framework for writing Java applications. Prior to versions 3.31.0, 3.27.2, and 3.20.5, a vulnerability exists in the HTTP layer of Quarkus REST related to response handling. When a response is being written, the framework waits for previously written response chunks to be fully transmitted before proceeding. If the client connection is dropped during this waiting period, the associated worker thread is never released and becomes permanently blocked. Under sustained or repeated occurrences, this can exhaust the available worker threads, leading to degraded performance, or complete unavailability of the application. This issue has been patched in versions 3.31.0, 3.27.2, and 3.20.5. A workaround involves implementing a health check that monitors the status and saturation of the worker thread pool to detect abnormal thread retention early.
EPSS 0.01% · 2.0th percentile
Risk Scores
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Maven | io.quarkus:quarkus-rest | 0, 3.21.0, 3.30.0 |
| quarkus | quarkus | 3.30.0, 0, 3.21.0 |
| quarkusio | quarkus | >= 3.30.0, < 3.31.0, >= 3.21.0, < 3.27.2, < 3.20.5 |
Exploit Intelligence
- CIRCL seen: CVE-2025-66560 (circl-sighting)
- CIRCL seen: CVE-2025-66560 (circl-sighting)
- https://github.com/quarkusio/quarkus/security/advisories/GHSA-5rfx-cp42-p624 (circl)
Timeline
- Jan 7, 2026 CVE Published
- Jan 7, 2026 PoC Published
- Jan 8, 2026 EPSS Score
- Jan 8, 2026 PoC Published
- Jan 11, 2026 EPSS Score
- Jan 14, 2026 EPSS Score
- Jan 18, 2026 EPSS Score
- Jan 21, 2026 EPSS Score
- Jan 24, 2026 EPSS Score
- Jan 27, 2026 EPSS Score
- Jan 30, 2026 EPSS Score
- Feb 2, 2026 EPSS Score