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CVE-2026-78669GO-2026-6611BIT-GOLANG-2026-78669

Excessive CPU consumption from repeated initial window changes in net/http

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 1.26.9, 1.27.2, 0.60.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

A malicious HTTP/2 peer can cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • net/http

    fixed in 1.26.9

  • net/http/internal/http2

    From 1.27.0-0 · fixed in 1.27.2

  • golang.org/x/net/http2

    fixed in 0.60.0

  • stdlibGo

    fixed in 1.26.9

  • stdlibGo

    From 1.27.0-0 · fixed in 1.27.2

  • golang.org/x/netGo

    fixed in 0.60.0

References 6

go.dev

groups.google.com

pkg.go.dev

CVE-2026-78669: Excessive CPU consumption from repeated initial window changes in net/http | cve.now