Is CVE-2021-21426 actively exploited?

No active exploitation of CVE-2021-21426 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-21426 be exploited remotely?

Yes. CVE-2021-21426 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-21426?

CVE-2021-21426 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-21426

CWE-502Published: April 21, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

Magento-lts is a long-term support alternative to Magento Community Edition (CE). In magento-lts versions 19.4.12 and prior and 20.0.8 and prior, there is a vulnerability caused by the unsecured deserialization of an object. A patch in versions 19.4.13 and 20.0.9 was back ported from Zend Framework 3. The vulnerability was assigned CVE-2021-3007 in Zend Framework.

NVD Source

Technical Analysis

CVE-2021-21426 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

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 9.8.

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