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 operations such as Parse UDP to inject malicious JavaScript into HTML output. This issue is fixed in version 11.2.0.

CVSS 3.1

5.0CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 15% of CVEs (scores of 2026-10-25)

CWEs

CWE-79, CWE-1321

Published

2026-07-08

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Packages (OSV)

References

• https://github.com/gchq/CyberChef/commit/85db3be5d0096859b810f0e8d3e151d5dc9b948f
• https://github.com/gchq/CyberChef/issues/2568
• https://github.com/gchq/CyberChef/pull/2569
• https://github.com/gchq/CyberChef/releases/tag/v11.2.0
• https://github.com/gchq/CyberChef/security/advisories/GHSA-fx6f-382r-j72c

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