CVE-2026-78663Critical· 9.1▾ MidnightThe 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 da…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 50.1 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Oct 9.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Last analysed / modified upstream
0.2%
— → 5.3
none → medium
5.3 → 9.1
medium → critical
0.2% → 0.6%
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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
stdlib < 1.26.9stdlib >= 1.27.0-0, < 1.27.2golang.org/x/net < 0.60.0Patched in:
stdlib 1.26.9stdlib 1.27.2golang.org/x/net 0.60.0Source: https://osv.dev/vulnerability/GO-2026-6612
Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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