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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Eclipse Foundation Eclipse Jetty unaffected
Version Status Constraints
12.1.0 affected ≤ 12.1.10
12.0.0 affected ≤ 12.0.37
11.00 affected ≤ 11.0.31
10.0.0 affected ≤ 10.0.31
9.4.36 affected ≤ 9.4.63

No data.

No data.

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/jetty/jetty.project/security/advisories/GHSA-gpg9-4257-cfm3 cve-icon cve-icon
History

Tue, 08 Sep 2026 14:15:00 +0000

Type Values Removed Values Added
Title HTTP/2 Race Condition Causing Server Denial of Service in Jetty

Tue, 08 Sep 2026 13:45:00 +0000

Type Values Removed Values Added
First Time appeared Eclipse
Eclipse jetty
Vendors & Products Eclipse
Eclipse jetty

Tue, 08 Sep 2026 12:45:00 +0000

Type Values Removed Values Added
Description 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.
Weaknesses CWE-400
References
Metrics cvssV4_0

{'score': 8.7, 'vector': '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: eclipse

Published:

Updated: 2026-09-08T12:28:51.669Z

Reserved: 2026-06-18T11:34:22.081Z

Link: CVE-2026-12611

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-09-08T13:17:17.150

Modified: 2026-09-08T14:15:01.243

Link: CVE-2026-12611

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-08T14:00:19Z

Weaknesses