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Ultrajson_project vulnerabilities

Known CVEs affecting Ultrajson_project products, prioritized by severity, with SEC.co remediation and detection guidance.

1 published vulnerability

Known exploited (KEV)CriticalHighMediumAll recent
  • CVE-2026-54911MEDIUM 6.5

    UltraJSON, a widely-used C-based JSON library with Python bindings, contains a flaw in how it handles invalid UTF-8 sequences when the reject_bytes option is disabled. Rather than rejecting malformed data, the library silently converts these corrupted byte sequences into different Unicode characters, allowing attackers to bypass input validation checks and potentially manipulate data integrity. This vulnerability affects versions prior to 5.13.0 and requires developers to upgrade to patch this issue.