CVE-2026-78660

high

Description

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.

References

https://pkg.go.dev/vuln/GO-2026-6610

https://groups.google.com/g/golang-announce/c/U2fTuyDJznI

https://go.dev/issue/81115

https://go.dev/cl/836385

https://go.dev/cl/835145

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-95425

Details

Source: Mitre, NVD

Published: 2026-10-08

Updated: 2026-10-09

Named Vulnerability: GO-2026-6610

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N

Severity: High

CVSS v3

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Severity: High

EPSS

EPSS: 0.00188