CVE-2025-8671
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).
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.62%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 3.62% probability · 89th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-404
- Source
- cret@cert.org
EPSS 3.6% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://galbarnahum.com/made-you-reset
- https://github.com/h2o/h2o/commit/4729b661e3c6654198d2cc62997e1af58bef4b80
- https://github.com/h2o/h2o/security/advisories/GHSA-mrjm-qq9m-9mjq
- https://gitlab.isc.org/isc-projects/bind9/-/issues/5325
- https://kb.cert.org/vuls/id/767506
- https://support2.windriver.com/index.php?page=security-notices
- https://varnish-cache.org/security/VSV00017.html
- https://www.fastlystatus.com/incident/377810
- https://www.suse.com/support/kb/doc/?id=000021980
- http://www.openwall.com/lists/oss-security/2025/08/13/6
- http://www.openwall.com/lists/oss-security/2025/09/18/1
- https://deepness-lab.org/publications/madeyoureset/
- https://github.com/Kong/kong/discussions/14731
- https://github.com/envoyproxy/envoy/issues/40739
- https://github.com/varnish/hitch/issues/397
- https://www.imperva.com/blog/madeyoureset-turning-http-2-server-against-itself/
- https://www.kb.cert.org/vuls/id/767506
- https://gitlab.isc.org/isc-projects/bind9/-/issues/5325
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.