CVE-2026-55691 is a high-severity cross-site scripting (XSS) vulnerability in starcitizenwiki/embedvideo (composer), affecting versions <= 4.0.0. It is fixed in 4.1.0.
Summary The user supplied class value is fed directly into the sprintf call that creates HTML. You can add a quote to escape the class and then inject arbitrary html/javascript to the final output. Details The template here adds a figure with a class that is substituted in. This value is provided to sprintf here, an unescaped version of the class supplied by the user. PoC Note the double quote immediately following the single quote to escape the class attribute in the template: Impact Arbitrary HTML can be inserted into the DOM by any user on any page, allowing for JavaScript to be executed.
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-2026-55691 has a CVSS score of 8.6 (High). The vector is network-reachable, no privileges required, and no user interaction. 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 (4.1.0). Upgrading removes the vulnerable code path.
composer
starcitizenwiki/embedvideo (<= 4.0.0)starcitizenwiki/embedvideo → 4.1.0 (composer)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 instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-55691 is reachable in your applications. Explore open-source security for your team.
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Upgrade starcitizenwiki/embedvideo to 4.1.0 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-55691 is a high-severity cross-site scripting (XSS) vulnerability in starcitizenwiki/embedvideo (composer), affecting versions <= 4.0.0. It is fixed in 4.1.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
CVE-2026-55691 has a CVSS score of 8.6 (High). 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.
starcitizenwiki/embedvideo (composer) versions <= 4.0.0 is affected.
Yes. CVE-2026-55691 is fixed in 4.1.0. Upgrade to this version or later.
Whether CVE-2026-55691 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
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.
Upgrade starcitizenwiki/embedvideo to 4.1.0 or later.