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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-25294
• https://github.com/snoopysecurity/snoopysecurity.github.io/blob/master/web-application-security/2021/01/16/09_opencats_php_object_injection.html
• https://snoopysecurity.github.io/web-application-security/2021/01/16/09_opencats_php_object_injection.html
• https://www.opencats.org/news/