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CVE-2026-63430VulnerabilityPublished Updated

Rust ammonia: Prior to 3.3.2, 4.0.2, and 4.1.3, applications that explicitly allow the math tag, annotation-xml, and

Affects rust-ammoniaSource GCVE Database

0
Authoritative record:CVE-2026-63430· Medium 6.3

Not known to be exploited · CVSS 6.3 Medium · fixed in 3.3.2 : update rust-ammonia when convenient.

Data as of 28 Oct 2026, 22:28 UTC

CVSS 4.0 base score
6.3Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 3.3.2
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSrust-ammoniapkg:deb/ubuntu/rust-ammonia?arch=source&distro=resoluteOther threatsAffected
  • =4.0.0-3
  • =4.1.2-1
Fixed in–
Ubuntu 24.04 LTSrust-ammoniapkg:deb/ubuntu/rust-ammonia?arch=source&distro=nobleOther threatsAffected
  • =3.2.1-1
  • =3.3.0-1
Fixed in–
Ubuntu 22.04 LTSrust-ammoniapkg:deb/ubuntu/rust-ammonia?arch=source&distro=jammyOther threatsAffected
  • =3.1.0-2
  • =3.1.2-1
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

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.

References

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