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    CVE-2020-26870

    Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.

    Published:Oct 7, 2020
    Last Modified:Nov 21, 2024
    EPS:Oct 7, 2020
    EPSS Score:0.0029
    CVSS Score:6.1

    Affected Products

    Vendor
    Cure53
    Product
    Dompurify
    Vendor
    Debian
    Product
    Debian Linux
    Vendor
    Microsoft
    Product
    Visual Studio 2017
    Vendor
    Microsoft
    Product
    Visual Studio 2019
    Vendor
    Oracle
    Product
    Application Express

    Exploits

    https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/

    Related CVEs

    CVE-2026-75838 (CVSS 5.1) — DOMPurify before 3.4.13 contains a cross-site scripting vulnerability in IN_PLACE sanitization where element-r…
    CVE-2026-66010 (CVSS 5.1) — DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELE…
    CVE-2026-65914 (CVSS 5.3) — DOMPurify before 3.3.2 contains a mutation-XSS vulnerability when sanitized HTML is reinserted into special pa…
    CVE-2026-65913 (CVSS 5.1) — DOMPurify before 3.3.2 contains a prototype pollution vulnerability in USE_PROFILES mode that allows attackers…
    CVE-2026-65912 (CVSS 5.1) — DOMPurify before 3.3.2 contains a URI validation bypass vulnerability when ADD_ATTR is provided as a predicate…
    CVE-2026-65911 (CVSS 5.1) — In DOMPurify through 3.3.3, function predicates supplied via ADD_ATTR or ADD_TAGS to DOMPurify.sanitize() pers…
    CVE-2026-65904 (CVSS 2.3) — DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates fr…
    CVE-2026-65903 (CVSS 5.1) — DOMPurify before 3.4.0 contains a logic error in the ADD_TAGS function where short-circuit evaluation allows f…
    CVE-2026-65902 (CVSS 5.3) — DOMPurify before 3.4.7 (affected versions <= 3.4.5) passes direct references to the module-level DEFAULT_ALLOW…
    CVE-2026-65901 (CVSS 5.1) — DOMPurify through 3.4.6 contains a cross-site scripting vulnerability in IN_PLACE mode that trusts attacker-co…

    References

    https://github.com/cure53/DOMPurify/commit/02724b8eb048dd219d6725b05c3000936f11d62d
    https://github.com/cure53/DOMPurify/compare/2.0.16...2.0.17
    https://lists.debian.org/debian-lts-announce/2020/10/msg00029.html
    https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-26870
    https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/
    https://www.oracle.com//security-alerts/cpujul2021.html
    https://github.com/cure53/DOMPurify/commit/02724b8eb048dd219d6725b05c3000936f11d62d
    https://github.com/cure53/DOMPurify/compare/2.0.16...2.0.17
    https://lists.debian.org/debian-lts-announce/2020/10/msg00029.html
    https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-26870
    https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/
    https://www.oracle.com//security-alerts/cpujul2021.html

    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