CVE-2021-25294

OpenCATS through 0.9.5-3 unsafely deserializes index.php?m=activity requests, leading to remote...

9.8 Critical

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

11.3%Up 9.5 points since Apr 14, 2021

What each source reports

NVD Score used 9.8

Record: CVE-2021-25294
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 10.0 HighAV:N/AC:L/Au:N/C:C/I:C/A:C
Weakness: CWE-502
Updated: 2026-11-02

CVE List No score

Record: CVE-2021-25294
Updated: 2026-11-02

EUVDEUVD-2021-12194 No score

Record: EUVD-2021-12194
Updated: 2026-11-03

GitHub AdvisoriesGHSA-wvm3-h9rx-qj3q No score

OpenCATS through 0.9.5-3 unsafely deserializes index.php?m=activity requests, leading to remote...

Record: GHSA-wvm3-h9rx-qj3q
Weakness: CWE-502
Updated: 2026-11-02

OSV 9.8

Record: CVE-2021-25294
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

Affected products

opencats

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-25294 is a critical vulnerability (CVSS 9.8) in Opencats, published January 18, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 11.3%, the 96th percentile. No source names a fixed version.