CVE-2026-116803: XSS (CVSS 6.1)

Description

DOMPurify before 3.4.17 contains a cross-site scripting vulnerability that allows attackers to keep event handlers armed when an IN_PLACE hook removes a parent or sibling node. Attacker markup in detached subtrees is never walked or neutralized, so handlers like img onerror fire after sanitize() returns, causing DOM XSS.

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CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://github.com/cure53/DOMPurify/security/advisories/GHSA-mrv2-3pqr-j5jr https://www.vulncheck.com/advisories/dompurify-before-3.4.17-dom-xss-via-in-place-hook-detached-subtrees

Frequently Asked Questions

What is CVE-2026-116803? +

DOMPurify before 3.4.17 contains a cross-site scripting vulnerability that allows attackers to keep event handlers armed when an IN_PLACE hook removes a parent or sibling node. Attacker markup in detached subtrees is never walked or neutralized, so handlers like img onerror fire after sanitize() returns, causing DOM XSS. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-116803? +

CVE-2026-116803 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-116803? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-116803