---
id: CVE-2026-12611
title: >-
  A client may issue HTTP/2 requests to a Jetty server that result in blocking
  writes that are never unblocked, eventually causing all threads to be blocked
  and the whole server to become unresponsive.





  This is caused by a race conditio…
summary: >-
  A client may issue HTTP/2 requests to a Jetty server that result in blocking
  writes that are never unblocked, eventually causing all threads to be blocked
  and the whole server to become unresponsive.





  This is caused by a race conditio…
severity: high
cvss: 8.7
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-400
  - CWE-367
vendor: Eclipse Foundation
product: Eclipse Jetty
affected:
  - eclipse_jetty >= 12.1.0 <= 12.1.10
  - eclipse_jetty >= 12.0.0 <= 12.0.37
  - eclipse_jetty >= 11.00 <= 11.0.31
  - eclipse_jetty >= 10.0.0 <= 10.0.31
  - eclipse_jetty >= 9.4.36 <= 9.4.63
published: '2026-09-08'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T11:17:12.777'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-12611'
references:
  - url: >-
      https://github.com/jetty/jetty.project/security/advisories/GHSA-gpg9-4257-cfm3
    label: emo@eclipse.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12611.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-12611'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2529778'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-12611'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-12611'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-08T13:22:30.453358Z'
cvssSource: cna
ingestedAt: '2026-09-08T15:33:26.983Z'
epss: 0.00253
epssPercentile: 0.14963
scores:
  cna: 8.7
  vendor: 7.5
---

## Overview

A client may issue HTTP/2 requests to a Jetty server that result in blocking writes that are never unblocked, eventually causing all threads to be blocked and the whole server to become unresponsive.




This is caused by a race condition in the server when handling RST_STREAM frames and GOAWAY frames sent by the client.




The race condition "resets" the HTTP2Flusher.terminated, previously set to a non-null value, to the null value, allowing entries to be enqueued in the flusher that however will never be processed. These unprocessed entries are the ones that would unblock the write-blocked threads.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: OpenShift Developer Tools and Services, Red Hat Offline Knowledge Portal, Red Hat AMQ Broker 7, Red Hat build of Apache Camel for Spring Boot 4, Red Hat build of Apicurio Registry 3, Red Hat Fuse 7, … · no fix planned: OpenShift Developer Tools and Services, Red Hat Offline Knowledge Portal · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12611.json)