---
id: CVE-2025-66560
title: >-
  Quarkus is a Cloud Native, (Linux) Container First framework for writing Java
  applications
summary: >-
  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
  respo…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
vendor: quarkus
product: quarkus
affected:
  - quarkus < 3.20.5
  - 'quarkus >= 3.21.0, < 3.27.2'
  - 'quarkus >= 3.30.0, < 3.31.0'
patched:
  - quarkus 3.31.0
published: '2026-01-07'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T23:10:00.237'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-66560'
references:
  - url: >-
      https://github.com/quarkusio/quarkus/security/advisories/GHSA-5rfx-cp42-p624
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00388
epssPercentile: 0.30459
ingestedAt: '2026-09-30T22:27:27.734Z'
---

## Overview

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

- `quarkus < 3.20.5`
- `quarkus >= 3.21.0, < 3.27.2`
- `quarkus >= 3.30.0, < 3.31.0`

## Remediation

Upgrade past the affected range:

- `quarkus 3.31.0`