Is CVE-2021-21956 actively exploited?

No active exploitation of CVE-2021-21956 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-21956 be exploited remotely?

No. CVE-2021-21956 requires local access to exploit.

What is the CVSS score of CVE-2021-21956?

CVE-2021-21956 has a CVSS score of 7.8 (HIGH).

HOME VULNERABILITIESCVE-2021-21956

HIGH

CVE-2021-21956

CWE-502Published: April 14, 2022· Updated: Jun 17, 2026

7.8

CVSS v3.1

Official Description

A php unserialize vulnerability exists in the Ai-Bolit functionality of CloudLinux Inc Imunify360 5.10.2. A specially-crafted malformed file can lead to potential arbitrary command execution. An attacker can provide a malicious file to trigger this vulnerability.

NVD Source

Technical Analysis

CVE-2021-21956 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.8.

From a weakness classification perspective (CWE-502): Insecure deserialization vulnerabilities allow attackers to inject malicious objects during deserialization, potentially enabling remote code execution.