CVE-2026-56853GO-2026-6089BIT-GOLANG-2026-56853
Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.25.13, 1.26.6, 1.27.0-rc.3
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- net/http
fixed in 1.25.13; From 1.26.0-0 · fixed in 1.26.6; From 1.27.0-0 · fixed in 1.27.0-rc.3
- stdlibGo
fixed in 1.25.13; From 1.26.0-0 · fixed in 1.26.6; From 1.27.0-0 · fixed in 1.27.0-rc.3