YouTube Showcase attachment titles permit Author stored XSS
YouTube Showcase through 4.0.4 lets an Author create an attachment whose post_title contains an attribute-breaking payload, then reference it through the emd_mb_meta shortcode. EMD_MB_Helper::image_info() returns the raw title and EMD_MB_Helper::shortcode() inserts it into title="%s" with sprintf() but without esc_attr(). The script executes for visitors to the rendered page. The exact reporter payload is not disclosed.
- Component
- Video Gallery – YouTube Gallery, Playlist & Video Grid
- Plugin slug
youtube-showcase- Affected
- <= 4.0.4
- Safe version
4.0.5- Published
- Aug 16, 2026
This CVE was published Aug 16, 2026 and is one of 6 known issues for this plugin.
Update, patch or deactivate.
The official author release notes confirm remediation by 4.0.5; this does not establish that every intervening release was affected. Update the affected edition to 4.0.5 or a later maintained release on its supported branch. restrict Authors or disable the affected shortcode, review attachment titles and content, and invalidate privileged sessions if malicious pages were viewed. Official author release notes: https://wordpress.org/plugins/youtube-showcase/.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical description
The Youtube Showcase plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to, and including, 4.0.4 via the 'emd_mb_meta' shortcode. This is due to insufficient input sanitization and output escaping on attachment titles referenced by the shortcode's image field: EMD_MB_Helper::image_info() returns the attachment's raw post_title, and EMD_MB_Helper::shortcode() interpolates it into title="%s" HTML attributes via sprintf() without esc_attr(). This makes it possible for authenticated attackers, with author-level access and above (upload_files capability required to create the attachment, edit_posts/publish_posts to embed the shortcode), to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N