CVE-2026-0540 — dompurify
Fix: cure53/DOMPurify@302b51dCVE-2026-0540 is a Cross-site Scripting (XSS) vulnerability in dompurify. A fix is available for dompurify — see the affected versions and patch details below.
DOMPurify XSS via Missing Rawtext Elements in SAFE_FOR_XML
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-0540.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
dompurifynpmDescription
DOMPurify 3.1.3 through 3.3.1 and 2.5.3 through 2.5.8, fixed in 2.5.9 and 3.3.2, contain a cross-site scripting vulnerability that allows attackers to bypass attribute sanitization by exploiting five missing rawtext elements (noscript, xmp, noembed, noframes, iframe) in the SAFE_FOR_XML regex. Attackers can include payloads like </noscript><img src=x onerror=alert(1)> in attribute values to execute JavaScript when sanitized output is placed inside these unprotected rawtext contexts.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | dompurify | ≥ 3.1.3&&< 3.3.2 | 3.3.2npm install dompurify@3.3.2 |
| 📦npm | dompurify | ≥ 2.5.3&&< 2.5.9 | 2.5.9npm install dompurify@2.5.9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dompurify, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update dompurify to 3.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-0540 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-0540 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-0540. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-0540 in your dependencies?
O3 Security finds CVE-2026-0540 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.