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

CVE-2021-39392 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.3%.

Mylittlebackup CVE-2021-39392

CRITICAL

Deserialization of Untrusted Data (CWE-502)

2021-09-15 cve@mitre.org

Deserialization RCE Mylittlebackup

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

Sep 15, 2021 - 17:15 nvd

CRITICAL 9.8

DescriptionNVD

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.

AnalysisAI

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. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified as Deserialization of Untrusted Data (CWE-502), which allows attackers to execute arbitrary code through malicious serialized objects. 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. Affected products include: Mylittletools Mylittlebackup.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Avoid deserializing untrusted data. Use safe serialization formats (JSON). Implement integrity checks and type allowlists.