GO-2025-3503

    Dashboard / Vulnerabilities / GO-2025-3503

    GO-2025-3503

    Published: 12 Mar 2025Last Modified: 16 Apr 2026

    Summary: HTTP Proxy bypass using IPv6 Zone IDs in golang.org/x/net

    Details: Matching of hosts against proxy patterns can improperly treat an IPv6 zone ID as a hostname component. For example, when the NO_PROXY environment variable is set to "*.example.com", a request to "[::1%25.example.com]:80` will incorrectly match and not be proxied.

    References: https://go.dev/cl/654697, https://go.dev/issue/71984, https://groups.google.com/g/golang-announce/c/4t3lzH3I0eI/m/b42ImqrBAQAJ

    Affected packages

    Package

    Name: stdlib

    Purl: pkg:golang/stdlib

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -1.23.7

    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
    GO-2025-3503 | CVE-DB