XSS in Gchq Cyberchef
CVE-2026-57439
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…
Vulnerability class: XSS (Cross-Site Scripting)
CVSS v3 metric
CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Gchq Cyberchef — versions < 11.2.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-57439?
- CVE-2026-57439 is a medium-severity vulnerability in Gchq Cyberchef, classified under Cross-site Scripting. CVSS score: 5.0/10. Published 2026-07-08.
- How severe is CVE-2026-57439?
- Medium severity. CVSS v3 base score is 5.0 out of 10.