CVE-2026-57439
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.
Does this matter?
Lower severity and a low EPSS score (0.24%). Track it; it rarely justifies an emergency change on its own.
Description
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
- 5.0 MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 0.24% probability · 16th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-79, CWE-1321
- Source
- security-advisories@github.com
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
- https://github.com/gchq/CyberChef/security/advisories/GHSA-fx6f-382r-j72c
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.