The Easy GitHub Gist Shortcodes plugin for WordPress contains an insufficiently sanitized 'id' attribute of the gist shortcode. Authenticated users with Contributor level or higher can store malicious scripts that will execute whenever any user views a page containing the injected shortcode. This stored XSS can lead to session hijacking, defacement, or theft of sensitive data obtained from the victim’s browser.

The vulnerability affects the WordPress plugin Easy GitHub Gist Shortcodes by corsonr, specifically all releases up to and including version 1.0. Users who are running a vulnerable version on any WordPress installation are at risk.

With a CVSS score of 6.4 this issue is considered moderate in severity. The EPSS score is below 1 %, indicating a very low likelihood that the vulnerability will be publicly exploited at this time, and it is not yet listed in the CISA KEV catalog. Nonetheless, the exploit requires authenticated access at Contributor level or higher, so the risk is limited to sites that grant that level of permission. The stored nature of the attack means that any visitor to the compromised page will process the injected script, potentially compromising accounts and browsing sessions.