High
Security advisory
GCHQ CyberChef before 11.0.0 allows XSS via Show Base64 offsets, as demonstrated by the /#recipe=Show_Base64_offsets('%3Cscript substring.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-42615
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 03:21 UTC · Revision 1
Source evidence
GCHQ CyberChef before 11.0.0 allows XSS via Show Base64 offsets, as demonstrated by the /#recipe=Show_Base64_offsets('%3Cscript substring.
osv:CVE-2026-42615
Complete source record
{
"id": "09628e86c4b37c56d3403321c982d43b0473fd5d5c96d5b4ab062681e191b9e2",
"url": "https://osv.dev/vulnerability/CVE-2026-42615",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2026-42615",
"summary": "GCHQ CyberChef before 11.0.0 allows XSS via Show Base64 offsets, as demonstrated by the /#recipe=Show_Base64_offsets('%3Cscript substring.",
"evidence": "osv:CVE-2026-42615",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-42615",
"aliases": [
"CVE-2026-42615",
"GHSA-h4hv-92pp-pcjg"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/gchq/cyberchef",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "8de0ded56cfd59c284573faa4767e5d55733cc57"
},
{
"fixed": "9641ae07f92e9af50f10e978385465b2f4a36c4d"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "11.0.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"fixed": "9641ae07f92e9af50f10e978385465b2f4a36c4d"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42615.json"
}
}
],
"modified": "2026-10-28T02:30:33.032428757Z",
"provider": "osv",
"references": [
"https://github.com/gchq/CyberChef/compare/v10.24.0...v11.0.0",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42615.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-42615",
"https://github.com/gchq/CyberChef/issues/2344",
"https://github.com/gchq/CyberChef/commit/9641ae07f92e9af50f10e978385465b2f4a36c4d",
"https://github.com/gchq/CyberChef/pull/2346"
],
"provider_metadata": {
"cwe_ids": [
"CWE-79"
],
"cna_assigner": "mitre",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42615.json"
}
},
"related_cves": [
{
"value": "CVE-2026-42615",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 500008,
"published_at": "2026-04-29T02:55:53.171+00:00"
}