CVE-2025-8671

varnish: A mismatch caused by client-triggered server-sent stream resets between HTTP/2 specifications and the internal archit...

CVE-2025-8671 is fixed in 2 products on 1 platform, first by dnsdist 1.8.3-2ubuntu0.1~esm1, released August 13, 2025. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
7.5
high
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0364
89th percentile

A mismatch caused by client-triggered server-sent stream resets between HTTP/2 specifications and the internal architectures of some HTTP/2 implementations may result in excessive server resource consumption leading to denial-of-service (DoS). By opening streams and then rapidly triggering the server to reset them—using malformed frames or flow control errors—an attacker can exploit incorrect stream accounting. Streams reset by the server are considered closed at the protocol level, even though backend processing continues. This allows a client to cause the server to handle an unbounded number of concurrent streams on a single connection. This CVE will be updated as affected product details are released.

Where it's fixed

ProductFixed inFixReleased
Linux
dnsdist · Ubuntu 24.04.5 LTS (noble) 1.8.3-2ubuntu0.1~esm1 dnsdist 1.8.3-2ubuntu0.1~esm1 Aug 13, 2025
dnsdist · Ubuntu 25.10 (questing) 1.9.10-1ubuntu0.1 dnsdist 1.9.10-1ubuntu0.1 Sep 18, 2025
dnsdist · opensuse-leap 16.0 1.9.11-160000.1.1 OPENSUSE-SU-2026:20461-1 Apr 2, 2026
dnsdist · sles 15.7 1.9.11-150700.3.6.1 SUSE-SU-2026:0888-1 Mar 13, 2026
dnsdist · sles 16.0 1.9.11-160000.1.1 SUSE-SU-2026:20995-1 Apr 2, 2026
varnish · Debian 13.5 (trixie) 7.7.0-3+deb13u1 DEBIAN-CVE-2025-8671 Aug 13, 2025
varnish · opensuse-leap 16.0 7.7.3-bp160.1.1 OPENSUSE-SU-2026:22131-1 Nov 7, 2026

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