Sanitization bypass via short-circuited ADD_TAGS predicate
Published Jul 23, 2026 · Updated Jul 23, 2026
Sanitization bypass in Cure53 DOMPurify before 3.4.0 allows remote attackers to retain forbidden tags in sanitized output. The element filter at src/purify.ts lines 1117–1123 accepts a true ADD_TAGS predicate before evaluating the matching FORBID_TAGS entry. A consuming application must use functional ADD_TAGS with FORBID_TAGS and render attacker-controlled sanitized markup, which defeats its tag policy without interrupting service.
Summary
What happened
Sanitization bypass in Cure53 DOMPurify before 3.4.0 allows remote attackers to retain forbidden tags in sanitized output. The element filter at src/purify.ts lines 1117–1123 accepts a true ADD_TAGS predicate before evaluating the matching FORBID_TAGS entry. A consuming application must use functional ADD_TAGS with FORBID_TAGS and render attacker-controlled sanitized markup, which defeats its tag policy without interrupting service.
The record
- CVE
- CVE-2026-65903
- Published
- Jul 23, 2026
- Updated
- Jul 23, 2026
- Vendor
- Cure53
- Product
- DOMPurify
- Classifications
- CWE-697
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 23, 2026CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=0 <3.4.0
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
- Function-based ADD_TAGS bypass proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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