CVE-2025-8671
CVSS v3
7.5
HIGH
EPSS Score
3.7 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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.
Technical details
- Published
- 2025-08-13
Frequently asked questions
What is 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). 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.
Is CVE-2025-8671 actively exploited?
Active exploitation of CVE-2025-8671 has not been confirmed. Its EPSS score was 3.7% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2025-8671?
CVE-2025-8671 has a CVSS v3 base score of 7.5 (HIGH severity).
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