CVE-2026-57439: Gchq Cyberchef

Medium severity, CVSS 5.0. EPSS: 0.2% chance of exploitation in the next 30 days.

CyberChef is a web app for encryption, encoding, compression, and data analysis. Prior to 11.2.0, the Series Chart operation accepts __proto__ as a key while parsing user-supplied CSV, allowing prototype pollution that can be chained with operations such as Parse UDP to inject malicious JavaScript into HTML output. This issue is fixed in version 11.2.0.

Affected products

• Gchq Cyberchef: before 11.2.0 (fixed in 11.2.0)

Published 2026-07-08. Last modified 2026-07-10.