How severe is CVE-2026-0540?

No CVSS score has been assigned to CVE-2026-0540 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-0540?

CVE-2026-0540 affects the following packages: dompurify (npm), dompurify (npm). Ecosystems affected: npm.

How do I fix CVE-2026-0540?

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.

How do I detect CVE-2026-0540 in my npm dependencies?

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.

How do I mitigate CVE-2026-0540 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-0540 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-0540 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-0540?

CVE-2026-0540 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 33th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-0540?

CVE-2026-0540 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-0540 published, and has it been updated?

CVE-2026-0540 was published on March 3, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-0540 — dompurify

Fix: cure53/DOMPurify@302b51d

CVE-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

Also known asGHSA-v2wj-7wpq-c8vv

Published

Mar 3, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs33th percentile — riskier than 33% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

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.

6Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

dompurifynpm

99.9Mdownloads / week

Description

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

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`dompurify`	≥ 3.1.3&&< 3.3.2	3.3.2`npm install dompurify@3.3.2`
📦npm	`dompurify`	≥ 2.5.3&&< 2.5.9	2.5.9`npm install dompurify@2.5.9`

Affected Products

1 product · 2 configurations

Application

dompurifycure53

≥ 3.1.3 && ≤ 3.3.1

range

Detection & mitigation playbook

Open-source dependency

Detect
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
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

A moderate cross-site scripting (XSS) flaw was found in DOMPurify, an HTML sanitization library shipped in multiple Red Hat products, including Red Hat 3scale API Management Platform, Red Hat Ansible Automation Platform, Red Hat AMQ, OpenShift Virtualization console plugins, Cluster Observability Operator, and…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Source: Red Hat security advisory for CVE-2026-0540 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Ceph Storage 9.2	`rhceph/rhceph-9-rhel10:1790843527`	RHSA-2026:86618

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

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