CVE-2020-26961

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    CVE-2020-26961

    Published: 9 Dec 2020Last Modified: 16 Apr 2026

    Summary:

    Details: When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges from the responses as these do not make sense coming from a DoH resolver. However when an IPv4 address was mapped through IPv6, these addresses were erroneously let through, leading to a potential DNS Rebinding attack. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

    References: https://www.mozilla.org/security/advisories/mfsa2020-52/, https://www.mozilla.org/security/advisories/mfsa2020-50/, https://www.mozilla.org/security/advisories/mfsa2020-51/, https://bugzilla.mozilla.org/show_bug.cgi?id=1672528

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: N/A

    Events:

    Introduced- None
    Fixed -None

    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
    CVE-2020-26961 | CVE-DB