CVE-2025-66560
Quarkus REST has potential worker thread starvation when HTTP connection is closed while waiting to write
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
5.9
Quarkus REST has potential worker thread starvation when HTTP connection is closed while waiting to write
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.
- Record
CVE-2025-66560- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
EUVDEUVD-2026-1178
5.9
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.
- Record
EUVD-2026-1178- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-5rfx-cp42-p624
5.9
Quarkus REST has potential worker thread starvation when HTTP connection is closed while waiting to write
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.
Workarounds
For versions without the fix applied, it is recommended to implement a health check that monitors the status and saturation of the worker thread pool. This helps detect abnormal thread retention early and allows operators to take corrective action before the application’s responsiveness is impacted.
Credits
CVE reported by Shaswata Jash, Nokia
- Record
GHSA-5rfx-cp42-p624- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
NVD
5.9
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.
- Record
CVE-2025-66560- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
OSV
5.9
Quarkus REST has potential worker thread starvation when HTTP connection is closed while waiting to write
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.
- Record
CVE-2025-66560- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
OSVGHSA-5rfx-cp42-p624
5.9
Quarkus REST has potential worker thread starvation when HTTP connection is closed while waiting to write
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.
Workarounds
For versions without the fix applied, it is recommended to implement a health check that monitors the status and saturation of the worker thread pool. This helps detect abnormal thread retention early and allows operators to take corrective action before the application’s responsiveness is impacted.
Credits
CVE reported by Shaswata Jash, Nokia
- Record
GHSA-5rfx-cp42-p624- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
io.quarkus:quarkus-restMaven |
before 3.20.5 | 3.20.5 |
io.quarkus:quarkus-restMaven |
3.21.0 up to 3.27.2 | 3.27.2 |
io.quarkus:quarkus-restMaven |
3.30.0 up to 3.31.0 | 3.31.0 |
io.quarkus:quarkus-restMaven |
before 3.20.5, plus listed versions 3.10.03.10.0.CR13.10.13.10.23.11.0 Show 45 moreShow less3.11.0.CR13.11.13.11.23.11.33.12.03.12.0.CR13.12.13.12.23.12.33.13.03.13.0.CR13.13.13.13.23.13.33.14.03.14.0.CR13.14.13.14.23.14.33.14.43.15.03.15.0.CR13.15.13.15.23.15.33.15.3.13.15.43.15.53.15.63.15.6.13.15.6.23.15.73.16.03.16.0.CR13.16.13.16.23.16.33.16.43.17.03.17.0.CR13.17.13.17.23.17.33.17.43.17.5 |
3.20.5 |
io.quarkus:quarkus-restMaven |
3.21.0 up to 3.27.2, plus listed versions 3.21.13.21.23.21.33.21.43.22.0 Show 32 moreShow less3.22.0.CR13.22.13.22.23.22.33.23.03.23.0.CR13.23.13.23.23.23.33.23.43.24.03.24.0.CR13.24.13.24.23.24.33.24.43.24.53.25.03.25.0.CR13.25.13.25.23.25.33.25.43.26.03.26.0.CR13.26.13.26.23.26.33.26.43.27.03.27.0.CR13.27.1 |
3.27.2 |
io.quarkus:quarkus-restMaven |
3.30.0 up to 3.31.0, plus listed versions 3.30.13.30.23.30.33.30.43.30.5 Show 4 moreShow less3.30.63.30.73.30.83.31.0.CR1 |
3.31.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-66560 is a medium vulnerability (CVSS 5.9) in Quarkus, published January 7, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 32nd percentile. Fixed in io.quarkus:quarkus-rest 3.20.5.
References
Left out here: 31 versions. The JSON record has them.