CVE-2026-54911

Description

UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.13.0, ujson.dumps() (or ujson.dump() or ujson.encode()) have a reject_bytes=False option. When set, they may accept malformed or truncated UTF-8 byte sequences, silently rewriting them into different Unicode characters instead of rejecting them. This leads to input validation bypass and data integrity issues. This vulnerability is fixed in 5.13.0.

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Produits concernés

• ultrajson
• Ultrajson project ultrajson

Scores CVSS

Faiblesses (CWE)

• CWE-20

Références

• https://github.com/ultrajson/ultrajson/commit/169eaf36b1116fece5034ee79a7a0ef3f6deedcf Patch
• https://github.com/ultrajson/ultrajson/releases/tag/5.13.0 ProductRelease Notes
• https://github.com/ultrajson/ultrajson/security/advisories/GHSA-3j69-69wj-xqx2 MitigationPatchVendor Advisory

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories