CVE-2021-25294: Opencats

Critical severity, CVSS 9.8. EPSS: 10.9% chance of exploitation in the next 30 days.

OpenCATS through 0.9.5-3 unsafely deserializes index.php?m=activity requests, leading to remote code execution. This occurs because lib/DataGrid.php calls unserialize for the parametersactivity:ActivityDataGrid parameter. The PHP object injection exploit chain can leverage an __destruct magic method in guzzlehttp.

Affected products

• Opencats Opencats: up to and including 0.9.5-3

Published 2021-01-18. Last modified 2026-06-17.