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VulnerabilityPublished

CVE-2026-41240: cure53 DOMPurify · Permissive List of Allowed Inputs

Affects cure53 DOMPurifySource CVE Database V5

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Not known to be exploited · CVSS 6.0 Medium : upgrade to 3.4.0 when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 4.0 base score
6.0Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.4.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade DOMPurify and dompurify to 3.4.0.

Affected software

ProductAffectedFixed in
cure53DOMPurifyAffected
  • <3.4.0
Fixed in
  • 3.4.0
npmdompurifypkg:npm/dompurifyOther threatsAffected
  • <3.4.0
Fixed in
  • 3.4.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to DOMPurify version 3.4.0 or later, where this issue is fixed. Users should verify that their sanitization configurations do not rely on the vulnerable behavior and ensure that FORBID_TAGS is properly enforced by using the patched version.

Description

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions prior to 3.4.0 have an inconsistency between FORBID_TAGS and FORBID_ATTR handling when function-based ADD_TAGS is used. Commit c361baa added an early exit for FORBID_ATTR at line 1214. The same fix was not applied to FORBID_TAGS. At line 1118-1123, when EXTRA_ELEMENT_HANDLING.tagCheck returns true, the short-circuit evaluation skips the FORBID_TAGS check entirely. This allows forbidden elements to survive sanitization with their attributes intact. Version 3.4.0 patches the issue.

References

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