CVE-2026-12611

jetty12: A client may issue HTTP/2 requests to a Jetty server that result in blocking writes that are never unblocked, eventua...

CVE-2026-12611 is fixed in jetty12 on 1 platform by DEBIAN-CVE-2026-12611 (version 12.0.39-1), released September 8, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
n/a
No vendor severity
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0043
37th percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
jetty12 · Debian 14 12.0.39-1 DEBIAN-CVE-2026-12611 Sep 8, 2026

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