CVE-2026-56853 PUBLISHED

Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http

Assigner: Go
Reserved: 23.06.2026 Published: 13.08.2026 Updated: 14.08.2026

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.

Product Status

Vendor Go standard library
Product net/http
Versions Default: unaffected
  • affected from 0 to 1.25.13 (excl.)
  • affected from 1.26.0-0 to 1.26.6 (excl.)
  • affected from 1.27.0-0 to 1.27.0-rc.3 (excl.)

References

Problem Types

  • CWE-770: Allocation of Resources Without Limits or Throttling