CVE-2026-65904Public exploitNetwork attack vector

Cross-site scripting via cross-realm IN_PLACE bypass

Published Jul 23, 2026 · Updated Jul 23, 2026

Cross-site scripting in Cure53 DOMPurify 3.3.3 and earlier allows remote attackers to bypass sanitization through cross-realm DOM nodes. The private _isNode() function applies realm-specific instanceof Node to a foreign node, stringifies it, disables IN_PLACE, and leaves the original element unsanitized. Exploitation requires IN_PLACE mode, a node from another same-origin window, and later insertion into the main document, where retained script or event attributes execute in the browser.

CVSS severity2.3
Low
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Cure53 DOMPurify 3.3.3 and earlier allows remote attackers to bypass sanitization through cross-realm DOM nodes. The private _isNode() function applies realm-specific instanceof Node to a foreign node, stringifies it, disables IN_PLACE, and leaves the original element unsanitized. Exploitation requires IN_PLACE mode, a node from another same-origin window, and later insertion into the main document, where retained script or event attributes execute in the browser.

The record

CVE
CVE-2026-65904
Published
Jul 23, 2026
Updated
Jul 23, 2026
Vendor
Cure53
Product
DOMPurify
Classifications
CWE-754, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.4.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cure53 · DOMPurifyversion=0 <3.4.4

Published CVSS scores

4.7VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
2.3VulnCheckCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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