Cross-site scripting in gchq CyberChef
Priority LOW 31CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.
Summary
GCHQ CyberChef before 11.0.0 allows XSS via Show Base64 offsets, as demonstrated by the /#recipe=Show_Base64_offsets('%3Cscript substring.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00294 22nd percentileScored 2026-11-07
Fix Fixed CyberChef (GCHQ): 11.0.0cyberchef (npm): 11.0.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| gchq | CyberChef | before 11.0.0 | 11.0.0 | Patch available | CNA |
| — | cyberchef (npm) | before 11.0.0 | 11.0.0 | Patch available | GHSA-h4hv-92pp-pcjg |
- CyberChef Vendorgchq Affected before 11.0.0 Fixed in 11.0.0 Patch available CNA
- cyberchef (npm) Vendor— Affected before 11.0.0 Fixed in 11.0.0 Patch available GHSA-h4hv-92pp-pcjg
Remediation
- Fix · CNA CyberChef (GCHQ) Fixed in 11.0.0
- Fix · GHSA-h4hv-92pp-pcjg cyberchef (npm) Fixed in 11.0.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42615
- 2026-10-03 Alias added: GHSA-h4hv-92pp-pcjg
References
More gchq vulnerabilities
- TI-2026-41376 CyberChef: Prototype pollution in Series Chart operation CVSS 3.1MEDIUM 5.0
- TI-2025-18851 Stroom Authentication/Authorization Bypass when using AWS ALB CVSS 3.1CRITICAL 9.4
- TI-2018-16004 Stroom version <5.4.5 contains a XML External Entity (XXE) vulnerability in XML Parser… CVSS 3.0CRITICAL 10.0
- TI-2019-11632 CyberChef before 8.31.2 allows XSS in core/operations/TextEncodingBruteForce.mjs. CVSS 3.0MEDIUM 6.1
- TI-2019-08044 Cross-site scripting in stroom:stroom-app CVSS 3.1MEDIUM 6.1
- TI-2026-51128 CyberChef’s pretty-recipe parser vulnerable to client-side ReDoS / CPU exhaustion when parsing a malformed #recipe= URL CVSS 3.1MEDIUM 4.3
Sources
- CVE-2026-42615 · CVE Program
- CVE-2026-42615 · NVD
- FIRST EPSS
- GHSA-h4hv-92pp-pcjg · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences