DEBIAN-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.
Risk Scores
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Debian:11 | varnish | 6.5.1-1, 7.7.0-2, 7.7.0-3 |
| Debian:11 | h2o | 2.2.5+dfsg2, 2.2.5+dfsg2, 2.2.5+dfsg2 |
| Debian:12 | h2o | *, 0, 2.2.5+dfsg2-10 |
| Debian:12 | varnish | 7.7.1-1, 7.1.1-1.1, 7.1.1-1.2 |
| Debian:13 | varnish | 0, 7.7.3-1, 7.7.2-2 |
| Debian:14 | varnish | 7.7.0-3, 7.7.1-1, 0 |
Exploit Intelligence
- A Python script that checks if a web server is vulnerable to MadeYouReset (CVE-2025-8671) — an HTTP/2 DoS attack that bypasses Rapid Reset mitigations by tricking the server into resetting its own streams. It probes the target by sending a malformed WINDOW_UPDATE frame and inspects whether the server responds. (github-poc-repo)
- A Python script that checks if a web server is vulnerable to MadeYouReset (CVE-2025-8671) — an HTTP/2 DoS attack that bypasses Rapid Reset mitigations by tricking the server into resetting its own streams. It probes the target by sending a malformed WINDOW_UPDATE frame and inspects whether the server responds. (github-poc)
- CVE-2025-8671 vulnerability POC (github-poc-repo)
- CVE-2025-8671 vulnerability POC (github-poc)
- PoC éducatif pour la vulnérabilité CVE-2025-8671 (DoS HTTP/2 sur lighttpd). À utiliser uniquement en laboratoire local. (github-poc)
- PoC para validar vulnerabilidade MadeYouReset (github-poc)
- CVE-2025-25063 MadeYouReset HTTP/2 DDoS (github-poc)
- cli.rs (github-poc)
Timeline
- Aug 13, 2025 CVE Published
- Apr 28, 2026 CVE Updated