Is CVE-2021-39392 actively exploited?

No active exploitation of CVE-2021-39392 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-39392 be exploited remotely?

Yes. CVE-2021-39392 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-39392?

CVE-2021-39392 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-39392

CWE-502Published: September 15, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

The management tool in MyLittleBackup up to and including 1.7 allows remote attackers to execute arbitrary code because machineKey is hardcoded (the same for all customers' installations) in web.config, and can be used to send serialized ASP code.

NVD Source

Technical Analysis

CVE-2021-39392 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.