Vulnerabilities

Vulnerability · CVE-2026-63430

ammonia is a Rust library for repairing and securing untrusted HTML.

Published Oct 15, 2026 · catalog updated Oct 15, 2026 · ammonia is a Rust

Check if you run it

No confirmed exploitation is on record for CVE-2026-63430. EPSS is 0.55%. Act only if a listed version of ammonia is a Rust is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (ammonia is a Rust).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.55%
Remediation
Advisory link
Affected products
Debian:12 rust-ammonia · Debian:13 rust-ammonia · Debian:14 rust-ammonia · vendor rust-ammonia ammonia

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Debian:12 rust-ammonia3.2.1-1, 3.3.0-1, 4.0.0-1
  • Debian:13 rust-ammonia4.0.0-3, 4.1.1-1, 4.1.2-1
  • Debian:14 rust-ammonia4.0.0-3, 4.1.1-1, 4.1.2-1
  • vendor rust-ammonia ammoniaversion unspecified

How to fix CVE-2026-63430

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-63430. EPSS is 0.55%. Act only if a listed version of ammonia is a Rust is installed.

Which versions are affected?

Compare what you have installed with 3.2.1-1, 3.3.0-1, 4.0.0-1, 4.0.0-3, 4.1.1-1, 4.1.2-1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.55%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 15, 2026 · NIST NVD

    Detected

    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 aft

  2. Oct 15, 2026 · NIST NVD

    Updated

    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 aft

  3. Oct 15, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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 aft

Sources

  • CVE.orgVulnerability recordCVE-2026-63430

    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 s

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-63430

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-2026-63430

    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 s

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryDEBIAN-CVE-2026-63430
    osv.dev

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.