CVE-2021-42110

SYSTEM privilege escalation via FTP DLL hijacking

Published Dec 8, 2021 · Updated May 30, 2025

DLL hijacking in the Allegro Windows FTP module before 3.3.4156.1 allows local users to execute commands as NT AUTHORITY\SYSTEM. The advisory does not identify the DLL, host executable, or search-path location involved in the module's unsafe library loading. The FTP module is not installed by default, and a standard Windows account is required to reach SYSTEM-level command execution.

CVSS severity7.8
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DLL hijacking in the Allegro Windows FTP module before 3.3.4156.1 allows local users to execute commands as NT AUTHORITY\SYSTEM. The advisory does not identify the DLL, host executable, or search-path location involved in the module's unsafe library loading. The FTP module is not installed by default, and a standard Windows account is required to reach SYSTEM-level command execution.

The record

CVE
CVE-2021-42110
Published
Dec 8, 2021
Updated
May 30, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1574.002
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 8, 2021CVE publishedPublication date reported by the CVE source.
  2. May 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.1MITRECVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.2NIST NVDAV:L/AC:H/Au:N/C:C/I:C/A:C
7.8ThalesCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1574.002Hijack Execution Flow: DLL Side-Loading

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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