CVE-2021-42255

SYSTEM privilege escalation via unsafe repair files

Published Apr 12, 2022 · Updated Aug 4, 2024

Temporary-file misuse in AppGuard Enterprise before 6.7.100.1 allows local users to gain SYSTEM privileges through MSI repair. The Windows Installer repair path performs SYSTEM-context file operations, including executing temporary files, in the invoking user's %TEMP% directory. Local access is sufficient to invoke repair and influence those files, resulting in code execution as SYSTEM.

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

What happened

Temporary-file misuse in AppGuard Enterprise before 6.7.100.1 allows local users to gain SYSTEM privileges through MSI repair. The Windows Installer repair path performs SYSTEM-context file operations, including executing temporary files, in the invoking user's %TEMP% directory. Local access is sufficient to invoke repair and influence those files, resulting in code execution as SYSTEM.

The record

CVE
CVE-2021-42255
Published
Apr 12, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-668, CWE-379, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 12, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8MandiantCVSS: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

CWE-668Exposure of Resource to Wrong Sphere
CWE-379Creation of Temporary File in Directory with Insecure Permissions
T1068Exploitation for Privilege Escalation

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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