CVE-2026-65902Public exploitNetwork attack vector

Sanitization bypass via persistent default allow-list mutation

Published Jul 23, 2026 · Updated Jul 23, 2026

Trust boundary violation in Cure53 DOMPurify before 3.4.7 allows remote attackers to bypass HTML sanitization via poisoned defaults. The hook event object exposes live DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets, so writes through data.allowedTags or data.allowedAttributes persist across later default-config sanitize calls. Exploitation requires an application hook to mutate those fields and attacker-controlled markup to be rendered; retained tags or attributes can execute script in a user's browser.

CVSS severity6.1
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Trust boundary violation in Cure53 DOMPurify before 3.4.7 allows remote attackers to bypass HTML sanitization via poisoned defaults. The hook event object exposes live DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets, so writes through data.allowedTags or data.allowedAttributes persist across later default-config sanitize calls. Exploitation requires an application hook to mutate those fields and attacker-controlled markup to be rendered; retained tags or attributes can execute script in a user's browser.

The record

CVE
CVE-2026-65902
Published
Jul 23, 2026
Updated
Jul 23, 2026
Vendor
Cure53
Product
DOMPurify
Classifications
CWE-693, CWE-501, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <3.4.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cure53 · DOMPurifyversion=0 <3.4.7

Published CVSS scores

5.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
6.1VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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-693Protection Mechanism Failure
CWE-501Trust Boundary Violation
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo