CVE-2026-42615

EUVD-2026-26191
GCHQ CyberChef before 11.0.0 allows XSS via Show Base64 offsets, as demonstrated by the /#recipe=Show_Base64_offsets('%3Cscript substring.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mitreCNA
7.2 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
gchqcyberchef
𝑥
< 11.0.0
CNA
Common Weakness Enumeration
References
https://github.com/gchq/CyberChef/commit/9641ae07f92e9af50f10e978385465b2f4a36c4d
https://github.com/gchq/CyberChef/compare/v10.24.0...v11.0.0
https://github.com/gchq/CyberChef/issues/2344
https://github.com/gchq/CyberChef/pull/2346