What’s Vulnerable › Vulnerabilities

CVE-2021-33436

• Severity: high (CVSS 7.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-04-28 · updated 2026-06-17

Description

NoMachine for Windows prior to version 6.15.1 and 7.5.2 suffer from local privilege escalation due to the lack of safe DLL loading. This vulnerability allows local non-privileged users to perform DLL Hijacking via any writable directory listed under the system path and ultimately execute code as NT AUTHORITY\SYSTEM.

Affected products

• NoMachine: from 6.0.0 before 6.15.1; from 7.0 before 7.5.2 — fixed in 6.15.1, 7.5.2

How to fix

Upgrade to a fixed version: NoMachine 6.15.1, 7.5.2. Check the vendor advisory for mitigations.

References

• https://github.com/active-labs/Advisories/blob/master/2021/ACTIVE-2021-001.md
• https://knowledgebase.nomachine.com/SU05S00223
• https://knowledgebase.nomachine.com/SU05S00224
• https://knowledgebase.nomachine.com/TR05S10236
• https://github.com/active-labs/Advisories/blob/master/2021/ACTIVE-2021-001.md
• https://knowledgebase.nomachine.com/SU05S00223
• https://knowledgebase.nomachine.com/SU05S00224
• https://knowledgebase.nomachine.com/TR05S10236

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