VulnerabilityAwaiting Analysis
CVE-2026-56853
When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface.
HIGH 7.5EPSS 0.57%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.57%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.
- 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
- 0.57% probability · 45th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-770
- Source
- security@golang.org
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.