What’s Vulnerable › Vulnerabilities
CVE-2025-66560: Quarkus REST has potential worker thread starvation when HTTP connection is closed while waiting to write
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-01-07 · updated 2026-10-07
- Weakness: CWE-770
Description
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.
Affected products
- quarkusio quarkus: before 3.20.5; from 3.21.0 before 3.27.2; from 3.30.0 before 3.31.0 — fixed in 3.20.5, 3.27.2, 3.31.0
How to fix
Upgrade to a fixed version: quarkusio quarkus 3.20.5, 3.27.2, 3.31.0. Check the vendor advisory for mitigations.
References
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