DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions prior to 3.4.0 have an inconsistency between FORBIDTAGS and FORBIDATTR handling when function-based ADDTAGS is used. Commit c361baa added an early exit for FORBIDATTR at line 1214. The same fix was not applied to FORBIDTAGS. At line 1118-1123, when EXTRAELEMENTHANDLING.tagCheck returns true, the short-circuit evaluation skips the FORBIDTAGS check entirely. This allows forbidden elements to survive sanitization with their attributes intact. Version 3.4.0 patches the issue.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41240.json",
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-183",
"CWE-79"
]
}{
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "3.4.0"
}
],
"cpe": "cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:*",
"source": [
"CPE_RANGE",
"REFERENCES"
]
}