Update Rust crate ammonia to v4.1.3 [SECURITY] (release/2.1) - autoclosed

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
ammonia	dependencies	patch	4.1.2 → 4.1.3

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mXSS in ammonia via MathML annotation-xml encoding strip

GHSA-9jh8-v38h-cvhr / RUSTSEC-2026-0193

More information

Details

If a certain set of MathML tags are enabled, an attacker can inject arbitrary JavaScript code into the user's browser.

The annotation-xml tag has slightly different behavior than the other "integration point"
tags in MathML and SVG, but ammonia didn't handle it, so it didn't correctly
strip the namespace-incompatible tags.

This vulnerability only has an effect when the math and annotation-xml tags
are both enabled, but the encoding attribute is disabled, because it relies
on the following sequence of steps:

1. User writes code like <math><annotation-xml encoding="text/html"><gadget></annotation-xml></math>.
2. Namespace filtering checks the DOM, and it passes. <gadget> is parsed as HTML.
3. Attribute filter strips it down to <math><annotation-xml><gadget></annotation-xml></math>. Because the encoding attribute is gone, <gadget> is now parsed as MathML.
4. The gadget is written in such a way that it exploits the parsing differences between HTML and MathML.

Additionally, the gadget can only be written using a tag that is parsed as raw text in HTML.
These elements are:

• title
• textarea
• xmp
• iframe
• noembed
• noframes
• plaintext
• noscript
• style
• script

Applications that do not explicitly allow any of these tags should not be affected, since none are allowed by default.

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Discovered by: ivan0912 (YesWeHack) · Date: 2026-06-29 · Found via local differential analysis and source review of ammonia's sanitisation pipeline; no third-party systems were tested.

Severity

Unknown

References

• https://crates.io/crates/ammonia
• https://rustsec.org/advisories/RUSTSEC-2026-0193.html

This data is provided by OSV and the Rust Advisory Database (CC0 1.0).

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