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CVE-2026-63430

CVE-2026-63430 · ammonia: mXSS in ammonia via MathML `annotation-xml` encoding strip

This page contains facts from public vulnerability sources. Check the original advisory before updating.

ammonia is a Rust library for repairing and securing untrusted HTML. Prior to 3.3.2, 4.0.2, and 4.1.3, applications that explicitly allow the math tag, annotation-xml, and at least one raw-text HTML element while disallowing the encoding attribute can permit mutation cross-site scripting. ammonia does not correctly implement annotation-xml's encoding-dependent MathML integration-point behavior after attribute filtering removes encoding, so the sanitizer validates a descendant under one namespace interpretation while the browser reparses the output under another. An attacker can use that namespace transition and an allowed raw-text HTML element to execute JavaScript when a user renders the sanitized output. The required tags are not enabled by default, so applications that do not explicitly allow them are not affected. This issue is fixed in versions 3.3.2, 4.0.2, and 4.1.3.

CVSS 6.3 · Medium · EPSS 0.6% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • ammonia

    Versions
    • < 3.3.2: Affected
    • >= 4.0.0, < 4.0.2: Affected
    • >= 4.1.0, < 4.1.3: Affected

    No fix published

  • rust-ammonia Debian:12

    Versions
    • 3.2.1-1
    • 3.3.0-1
    • 4.0.0-1
    • 4.0.0-2
    • 4.0.0-3
    • 4.1.1-1
    • 4.1.2-1
    • 4.1.2-2
    • 4.1.3-1
    • 4.1.4-1
    • 4.2.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • rust-ammonia Debian:13

    Versions
    • 4.0.0-3
    • 4.1.1-1
    • 4.1.2-1
    • 4.1.2-2
    • 4.1.3-1
    • 4.1.4-1
    • 4.2.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • rust-ammonia Debian:14

    Versions
    • 4.0.0-3
    • 4.1.1-1
    • 4.1.2-1
    • 4.1.2-2
    Affected ranges
    • ECOSYSTEM: < 4.1.3-1

    Update to 4.1.3-1

  • rust-ammonia Ubuntu:22.04:LTS

    Versions
    • 3.1.0-2
    • 3.1.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • rust-ammonia Ubuntu:24.04:LTS

    Versions
    • 3.2.1-1
    • 3.3.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • rust-ammonia Ubuntu:26.04:LTS

    Versions
    • 4.0.0-3
    • 4.1.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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