CVE-2026-42615

Cross‑Site Scripting in CyberChef’s Base64 Offset Feature

Published Apr 29, 2026 CVSS 3.1 · 7.2 High EPSS < 1% KEV · Not listed
Description
GCHQ CyberChef before 11.0.0 allows XSS via Show Base64 offsets, as demonstrated by the /#recipe=Show_Base64_offsets('%3Cscript substring.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-h4hv-92pp-pcjg CyberChef has a Cross-site Scripting issue
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title Cross‑Site Scripting in CyberChef’s Base64 Offset Feature
Type Values Removed Values Added
Description GCHQ CyberChef before 11.0.0 allows XSS via Show Base64 offsets, as demonstrated by the /#recipe=Show_Base64_offsets('%3Cscript substring.
First Time appeared Gchq
Gchq cyberchef
Weaknesses CWE-79
CPEs cpe:2.3:a:gchq:cyberchef:*:*:*:*:*:*:*:*
Vendors & Products Gchq
Gchq cyberchef
References
Metrics cvssV3_1

{'score': 7.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Apr 29, 2026, 1:14 PM
Reserved
Apr 29, 2026, 2:55 AM
Status
Awaiting Analysis
Published
Apr 29, 2026, 4:16 AM
Modified
Jul 24, 2026, 8:10 PM