GO-2026-6610

    Dashboard / Vulnerabilities / GO-2026-6610

    GO-2026-6610

    Published: 8 Oct 2026Last Modified: 8 Oct 2026

    Summary: HTTP/2 transport accepts malformed framing-related headers in net/http

    Details: 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://go.dev/cl/835145, https://go.dev/cl/836385, https://go.dev/issue/81115, https://groups.google.com/g/golang-announce/c/U2fTuyDJznI

    Affected packages

    Package

    Name: stdlib

    Purl: pkg:golang/stdlib

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -1.26.9

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High