CRITICAL 9.1 NVD
CVE-2026-78663
The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread p
The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.
References
- https://go.dev/cl/847187
- https://go.dev/cl/847310
- https://go.dev/issue/81743
- https://groups.google.com/g/golang-announce/c/U2fTuyDJznI
- https://groups.google.com/g/golang-announce/c/ZPwCyRUuGBs
This critical severity vulnerability with a CVSS score of 9.1 was published on 2026-10-08 via NVD.
Risk Timeline
CVE Disclosed2026-10-08 · 3 days ago
Remediation Resources
Analysis & PoC
go.dev/cl/847187Analysis & PoC
go.dev/cl/847310
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