Prototype pollution in DOMPurify - CVE-2026-41238
Published: April 20, 2026
Vulnerability identifier: #VU126559
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-41238
CWE-ID: CWE-1321
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 in a victim's browser.
The vulnerability exists due to improperly controlled modification of object prototype attributes in DOMPurify sanitize configuration handling when sanitizing user-supplied HTML with the default CUSTOM_ELEMENT_HANDLING behavior. A remote attacker can supply crafted HTML and leverage prior prototype pollution to execute arbitrary script in a victim's browser.
User interaction is required, and exploitation requires a prototype pollution primitive in the same execution context.
How to mitigate CVE-2026-41238
Install security update from vendor's website.