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Advisory record · GHSA-x43w-36pp-96g3

Missing case-insensitive matching for CSS url function

No CVSS score

Published by the GitHub Advisory Database at 16 Oct 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
ammoniacrates.io>=0.0.0-0, <4.1.8 || >=4.2.0, <4.2.44.1.8, 4.2.4
Identifiers
GHSA-x43w-36pp-96g3 · RUSTSEC-2026-0373
Published
16 Oct 2026
Updated
17 Oct 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The ammonia crate versions below 4.1.8 and from 4.2.0 up to 4.2.4 are affected. URL filtering in CSS sanitization is not applied when the CSS url function is written in uppercase, such as URL(""), because matching is case-sensitive. An attacker who can supply CSS content to an application configured this way can inject tracking pixels that bypass the intended restrictions, though the source says it does not allow XSS. Upgrade to ammonia 4.1.8 or 4.2.4.

Written 3 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

No source has published a CVSS score for this record yet.

  • CISA KEV Not listed.
  • EPSS No score.

Timeline

  1. 31 Oct 2026, 14:24 UTC First seen by agentprime
  2. 31 Oct 2026, 14:24 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.