Improper access control in DOMPurify - #VU137374
Published: July 13, 2026
Vulnerability identifier: #VU137374
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: N/A
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Cure53
Affected software:
DOMPurify
DOMPurify
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary script code.
The vulnerability exists due to improper access control in the CUSTOM_ELEMENT_HANDLING sanitization logic when processing allowed custom elements. A remote attacker can supply specially crafted HTML content to execute arbitrary script code.
The bypass affects the afterSanitizeElements hook and the payload becomes executable only after a custom element writes sanitized data into innerHTML.
Remediation
Install security update from vendor's website.