PatchSiren cyber security CVE debrief
CVE-2026-8887 konforti CVE debrief
The Listen Shortcode plugin for WordPress is vulnerable to Stored Cross-Site Scripting (XSS) in versions up to and including 1.0. The vulnerability exists in the `listenEmbedJS()` function, where user-supplied attributes (`src`, `start`, `end`) are echoed inside single-quoted HTML attributes without proper sanitization or output escaping. This allows authenticated attackers with contributor-level access or higher to inject arbitrary web scripts that execute when users access injected pages. The vulnerability was disclosed on 2026-05-27 and has been assigned a CVSS 3.1 score of 6.4 (Medium severity). The issue is tracked as CWE-79 (Improper Neutralization of Input During Web Page Generation).
- Vendor
- konforti
- Product
- Listen Shortcode
- CVSS
- MEDIUM 6.4
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-27
- Original CVE updated
- 2026-05-27
- Advisory published
- 2026-05-27
- Advisory updated
- 2026-05-27
Who should care
WordPress site administrators using the Listen Shortcode plugin; security teams monitoring WordPress plugin vulnerabilities; developers responsible for plugin security updates
Technical summary
The vulnerability stems from insufficient input sanitization and output escaping in the `listenEmbedJS()` function of the Listen Shortcode WordPress plugin. User-supplied attributes (`src`, `start`, `end`) are directly echoed into single-quoted HTML attributes without escaping, enabling stored XSS. Attackers with contributor+ privileges can craft malicious shortcodes that persist in posts/pages and execute in victims' browsers. The attack requires no user interaction beyond viewing the injected page, with network-based attack vector and low attack complexity.
Defensive priority
medium
Recommended defensive actions
- Update the Listen Shortcode WordPress plugin to a version newer than 1.0 if available, or remove the plugin if no patch is released
- Review existing posts and pages for malicious [listen] shortcode usage, particularly checking the src, start, and end attributes for suspicious JavaScript payloads
- Implement Content Security Policy (CSP) headers to mitigate impact of any stored XSS payloads
- Consider disabling unfiltered_html capability for contributor-level users if not required for business operations
- Monitor web access logs for unusual requests to pages containing [listen] shortcodes
Evidence notes
Vulnerability confirmed via WordPress plugin repository source code review (lines 22 and 43 of heganoo-shortcode.php) and Wordfence threat intelligence. CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.
Official resources
2026-05-27