GHSA-4VF6-MQ7W-3HP6

ZendFilterStripTags vulnerable to Cross-site Scripting when comments allowed

Zend_Filter_StripTags contained an optional setting to allow whitelisting HTML comments in filtered text. Microsoft Internet Explorer and several other browsers allow developers to create conditional functionality via HTML comments, including execution of script events and rendering of additional commented markup. By allowing whitelisting of HTML comments, a malicious user could potentially include XSS exploits within HTML comments that would then be rendered in the final output.

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.

GHSA-4VF6-MQ7W-3HP6 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 (1.7.9, 1.8.5, 1.9.7); upgrading removes the vulnerable code path.

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1. What is GHSA-4VF6-MQ7W-3HP6? GHSA-4VF6-MQ7W-3HP6 is a medium-severity cross-site scripting (XSS) vulnerability in zendframework/zendframework1 (composer), affecting versions >= 1.7.0, < 1.7.9. It is fixed in 1.7.9, 1.8.5, 1.9.7. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is GHSA-4VF6-MQ7W-3HP6? GHSA-4VF6-MQ7W-3HP6 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.
3. Which versions of zendframework/zendframework1 are affected by GHSA-4VF6-MQ7W-3HP6? zendframework/zendframework1 (composer) versions >= 1.7.0, < 1.7.9 is affected.
4. Is there a fix for GHSA-4VF6-MQ7W-3HP6? Yes. GHSA-4VF6-MQ7W-3HP6 is fixed in 1.7.9, 1.8.5, 1.9.7. Upgrade to this version or later.
5. Is GHSA-4VF6-MQ7W-3HP6 exploitable, and should I be worried? Whether GHSA-4VF6-MQ7W-3HP6 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
6. What actually determines whether GHSA-4VF6-MQ7W-3HP6 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.
7. How do I fix GHSA-4VF6-MQ7W-3HP6?
   • Upgrade zendframework/zendframework1 to 1.7.9 or later
   • Upgrade zendframework/zendframework1 to 1.8.5 or later
   • Upgrade zendframework/zendframework1 to 1.9.7 or later

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