Improper Handling of Unicode Encoding Affecting expat package, versions <2.8.5-r0


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.4% (33rd percentile)

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  • Snyk IDSNYK-ALPINE324-EXPAT-20066735
  • published24 Sept 2026
  • disclosed19 Sept 2026

Introduced: 19 Sep 2026

NewCVE-2026-93990  (opens in a new tab)
CWE-176  (opens in a new tab)

How to fix?

Upgrade Alpine:3.24 expat to version 2.8.5-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream expat package and not the expat package as distributed by Alpine. See How to fix? for Alpine:3.24 relevant fixed versions and status.

Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing lone high surrogates that consume the following code unit, causing Expat to pass unpaired surrogates to applications built with XML_UNICODE and to silently replace input characters in other builds.

CVSS Base Scores

version 3.1