Improper Handling of Unicode Encoding Affecting expat package, versions [,2.8.5)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CONAN-EXPAT-21707499
- published25 Oct 2026
- disclosed20 Sept 2026
- creditUnknown
Introduced: 20 Sep 2026
CVE-2026-93990 (opens in a new tab)How to fix?
Upgrade expat to version 2.8.5 or higher.
Overview
Affected versions of this package are vulnerable to Improper Handling of Unicode Encoding in the UTF-16 input handling process. An attacker can inject arbitrary XML markup by crafting UTF-16 encoded data with lone high surrogates that are not properly validated, which can hide markup characters from the parser and lead to unauthorized modification of XML content.