CVE-2021-42110VulnerabilityPublished 8 Dec 2021Updated 30 May 2025

CVE-2021-42110: n/a

Source CVE Database V5

Not known to be exploited · CVSS 7.1 High · fixed in 3.3.4156.1 : patch affected systems soon.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

7.1High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 22% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.3.4156.1

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

Attack Complexity: Low
Attack Vector: Adjacent
Availability: None
Confidentiality: High
Integrity: Low
Privileges Required: None
Scope: Unchanged
User Interaction: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Availability: None: There is no impact to availability within the impacted component.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Dec 2021
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
n/a n/a	Affected <3.3.4156.1	Fixed in 3.3.4156.1

AI-suggested

To mitigate this vulnerability, European organizations should first identify all instances of Allegro Windows deployed within their environments, specifically verifying if the FTP module is installed and active. Immediate steps include applying any available patches or updates from the software vendor; if no patches are currently available, organizations should consider disabling the FTP module to eliminate the attack vector. Implement strict access controls to limit standard user access on systems running Allegro Windows, reducing the risk of local exploitation. Employ application whitelisting and monitor for unauthorized DLL loading or suspicious DLL files in directories used by Allegro Windows. Conduct regular integrity checks on DLL files associated with the FTP module. Additionally, enhance endpoint detection and response (EDR) capabilities to detect privilege escalation attempts and anomalous process behaviors. Network segmentation can limit lateral movement if compromise occurs. Finally, maintain up-to-date backups and incident response plans to quickly recover from potential exploitation.

Description

An issue was discovered in Allegro Windows (formerly Popsy Windows) before 3.3.4156.1. A standard user can escalate privileges to SYSTEM if the FTP module is installed, because of DLL hijacking.

Impact

For European organizations, this vulnerability poses a serious threat, especially in environments where Allegro Windows is used with the FTP module enabled. Successful exploitation allows an attacker with standard user access to gain SYSTEM-level privileges, potentially leading to full system compromise. This can result in unauthorized access to sensitive data, disruption of critical services, and the ability to deploy further malware or ransomware. Given the high confidentiality impact, sensitive corporate or personal data could be exposed or exfiltrated. The vulnerability is particularly concerning in sectors with strict data protection requirements such as finance, healthcare, and government institutions across Europe. Additionally, organizations with remote or multi-user access environments are at increased risk since local access is required but no additional privileges or user interaction are needed. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits over time.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Jul 2025, 15:39 UTC

Technical details

References

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