CVE-2026-78660GO-2026-6610BIT-GOLANG-2026-78660
HTTP/2 transport accepts malformed framing-related headers 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 1.26.9, 1.27.2, 0.60.0
- 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
Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such headers to an HTTP/1 client when acting as a reverse proxy. If the HTTP/1 client also does not behave strictly enough, this can result in response smuggling.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- 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