CVE-2020-26956

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    CVE-2020-26956

    Published: 9 Dec 2020Last Modified: 16 Apr 2026

    Summary:

    Details: In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

    References: https://www.mozilla.org/security/advisories/mfsa2020-50/, https://www.mozilla.org/security/advisories/mfsa2020-51/, https://www.mozilla.org/security/advisories/mfsa2020-52/, https://bugzilla.mozilla.org/show_bug.cgi?id=1666300

    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-2020-26956 | CVE-DB