ammonia: mXSS in ammonia via MathML `annotation-xml` encoding strip
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.
CVE-2026-63430
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-63430
ammonia
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "rust-ammonia",
"product": "ammonia",
"versions": [
{
"status": "affected",
"version": "< 3.3.2"
},
{
"status": "affected",
"version": ">= 4.0.0, < 4.0.2"
},
{
"status": "affected",
"version": ">= 4.1.0, < 4.1.3"
}
]
}
]- Related CVEs
- CVE-2026-63430
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #30172 · Revision 1
- Added to Heist Feed
- Publisher date