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CVE-2025-66560VulnerabilityPublished

CVE-2025-66560: quarkusio quarkus · Unthrottled Resource Allocation

Affects quarkusio quarkusSource CVE Database V5

0

Not known to be exploited · CVSS 5.9 Medium · fixed in 3.31.0 : update quarkusio quarkus when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.31.0, 3.27.2, 3.20.5
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade quarkus to 3.31.0, 3.27.2 or 3.20.5; io.quarkus/quarkus to 3.20.5.

Affected software

ProductAffectedFixed in
quarkusioquarkusAffected
  • >=3.30.0 <3.31.0
  • >=3.21.0 <3.27.2
  • <3.20.5
Fixed in
  • 3.31.0
  • 3.27.2
  • 3.20.5
Mavenio.quarkus/quarkuspkg:maven/io.quarkus/quarkusOther threatsAffected
  • <3.20.5
Fixed in
  • 3.20.5

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. Upgrade all Quarkus deployments to versions 3.31.0, 3.27.2, or 3.20.5 or later where the vulnerability is patched. 2. Implement health checks that monitor the worker thread pool saturation and thread retention metrics to detect abnormal conditions early. 3. Configure application and infrastructure-level timeouts to minimize the duration worker threads remain blocked on dropped connections. 4. Employ network-level protections such as rate limiting and connection management to reduce the likelihood of sustained connection drops caused by malicious or unstable clients. 5. Use container orchestration health probes (e.g., Kubernetes readiness and liveness probes) to automatically restart unhealthy application instances exhibiting thread pool exhaustion. 6. Monitor application logs and metrics for signs of thread starvation or increased latency in response handling. 7. Educate development and operations teams about this vulnerability to ensure timely patching and monitoring. 8. Consider deploying Web Application Firewalls (WAFs) or API gateways that can help detect and mitigate abnormal client connection behaviors.

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.

References

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