CVE-2021-33436

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.

Published: 2022-04-28 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-33436 is rated Low Risk (33.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.04%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-33436

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-05-04 0.15% 0.04% -0.11%
2 2025-05-03 0.05% 0.15% +0.10%
3 2025-04-29 — 0.05% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-33436

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.3 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.3 5.9 [email protected]
6.2 2.0 MEDIUM
AV:L/AC:H/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 1.9 10.0 [email protected]

Weakness enumeration for CVE-2021-33436

Affected software / configurations for CVE-2021-33436

Vendor Product Version Raw CPE
nomachine nomachine >= 6.0.0, < 6.15.1 cpe:2.3:a:nomachine:nomachine:*:*:*:*:*:*:*:*
nomachine nomachine >= 7.0, < 7.5.2 cpe:2.3:a:nomachine:nomachine:*:*:*:*:*:*:*:*

References for CVE-2021-33436

cvelogic Threat Intelligence