GO-2026-6607

    Dashboard / Vulnerabilities / GO-2026-6607

    GO-2026-6607

    Published: 8 Oct 2026Last Modified: 8 Oct 2026

    Summary: Reject malformed ECH outer extension references in crypto/tls

    Details: Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and curb the memory amplification vector as a result.

    References: https://go.dev/cl/847312, https://go.dev/issue/81855, 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