CVE-2026-65904: DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates fr

Q: How do I fix CVE-2026-65904?

dompurify: upgrade to 3.4.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-65904 being exploited?

CVE-2026-65904 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-65904 affect?

CVE-2026-65904 affects dompurify. Severity is medium (CVSS 4.7). DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function

Q: How urgent is CVE-2026-65904?

Priority 26/100. Public exploit reference

Routine

MEDIUM 4.7UPGRADE

CVE-2026-65904 is a medium-severity flaw (CVSS 4.7) affecting dompurify. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function returns false for foreign-realm nodes, causing DOMPurify to stringify the element (yielding '[object HTMLDivElement]'), silently reset IN_PLACE to false, and return the unsanitized element unchanged with any XS

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	4.7 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-754
Published	2026-07-23
Last modified	2026-10-24

Publisher (CNA): VulnCheck · Vendor: cure53

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-23 14:18 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated Record last modified

cure53 dompurify UPGRADE

Affected: < 3.4.4

Fixed in: 3.4.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy dompurify || rpm -q dompurify || dompurify --version

2. UPGRADE to 3.4.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade dompurify

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade dompurify

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-65904?

dompurify: upgrade to 3.4.4. Exact commands for each OS are on this page.

Is CVE-2026-65904 being exploited?

CVE-2026-65904 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-65904 affect?

CVE-2026-65904 affects dompurify. Severity is medium (CVSS 4.7). DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function

How urgent is CVE-2026-65904?

Priority 26/100. Public exploit reference

Related CVEs

CVE-2026-65898 HIGH 7.2 UPGRADE DOMPurify before 3.4.11 fails to clone the ALLOWED_ATTR allowlist when setConfig() is used with an uponSanitiz
CVE-2026-65899 MEDIUM 6.1 UPGRADE DOMPurify 3.0.0 before 3.4.9 does not reset the retained Trusted Types policy when clearConfig() is called, so
CVE-2026-65902 MEDIUM 6.1 UPGRADE DOMPurify before 3.4.7 (affected versions <= 3.4.5) passes direct references to the module-level DEFAULT_ALLOW
CVE-2026-65911 MEDIUM 6.1 UPGRADE In DOMPurify through 3.3.3, function predicates supplied via ADD_ATTR or ADD_TAGS to DOMPurify.sanitize() pers
CVE-2026-65900 MEDIUM 6.1 UPGRADE DOMPurify versions >=3.0.0 and before 3.4.8, when configured with SAFE_FOR_TEMPLATES together with a DOM outpu

References

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