What is CVE-2026-61784?

CVE-2026-61784 is a medium-severity cross-site scripting (XSS) vulnerability in xhtml-purifier (npm), affecting versions <= 0.4.1. It is fixed in 0.4.3. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.

How severe is CVE-2026-61784?

CVE-2026-61784 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of xhtml-purifier are affected by CVE-2026-61784?

xhtml-purifier (npm) versions <= 0.4.1 is affected.

Is there a fix for CVE-2026-61784?

Yes. CVE-2026-61784 is fixed in 0.4.3. Upgrade to this version or later.

Is CVE-2026-61784 exploitable, and should I be worried?

Whether CVE-2026-61784 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-61784 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

CVE-2026-61784 in xhtml-purifier

Q: How severe is CVE-2026-61784?

CVE-2026-61784 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of xhtml-purifier are affected by CVE-2026-61784?

xhtml-purifier (npm) versions <= 0.4.1 is affected.

Q: Is there a fix for CVE-2026-61784?

Yes. CVE-2026-61784 is fixed in 0.4.3. Upgrade to this version or later.

Q: Is CVE-2026-61784 exploitable, and should I be worried?

Whether CVE-2026-61784 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-61784 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-61784?

Upgrade xhtml-purifier to 0.4.3 or later.

Summary

xhtml-purifier has HTML attribute-injection (sanitizer bypass) that leads to XSS

xhtml-purifier does not HTML-entity-encode attribute values when serializing its sanitized output. In attributeString() (XHTMLPurifier.js, around line 148) the attribute value is concatenated directly into a double-quoted attribute without encoding. As a result, an attacker-controlled value in any allowed attribute (class, style, title, alt, src, href) can include a double-quote character to break out of the attribute and inject an additional attribute, such as a JavaScript event handler (for example onmouseover or onerror). The injected handler survives sanitization and executes when the output is rendered, which is a sanitizer bypass leading to cross-site scripting. The fix HTML-entity-encodes attribute values before serialization.

Impact

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2026-61784 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.4.3); upgrading removes the vulnerable code path.

Affected versions

xhtml-purifier (<= 0.4.1)

Security releases

xhtml-purifier → 0.4.3 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade xhtml-purifier to 0.4.3 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

What is CVE-2026-61784? CVE-2026-61784 is a medium-severity cross-site scripting (XSS) vulnerability in xhtml-purifier (npm), affecting versions <= 0.4.1. It is fixed in 0.4.3. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
How severe is CVE-2026-61784? CVE-2026-61784 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of xhtml-purifier are affected by CVE-2026-61784? xhtml-purifier (npm) versions <= 0.4.1 is affected.
Is there a fix for CVE-2026-61784? Yes. CVE-2026-61784 is fixed in 0.4.3. Upgrade to this version or later.
Is CVE-2026-61784 exploitable, and should I be worried? Whether CVE-2026-61784 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-61784 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-61784? Upgrade xhtml-purifier to 0.4.3 or later.