CVE-2021-27766

SYSTEM privilege escalation via insecure MSI repair

Published May 6, 2022 · Updated Sep 17, 2024

Local privilege escalation in HCL BigFix Client 9.5 through 9.5.18 and 10 through 10.0.5 allows local users to gain SYSTEM access. A Windows Installer repair executes temporary files from the invoking user’s %TEMP% directory under the SYSTEM account. Any authenticated local Windows user can invoke the repair through the Windows Installer API or msiexec, enabling arbitrary code execution with SYSTEM privileges.

CVSS severity6.7
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Local privilege escalation in HCL BigFix Client 9.5 through 9.5.18 and 10 through 10.0.5 allows local users to gain SYSTEM access. A Windows Installer repair executes temporary files from the invoking user’s %TEMP% directory under the SYSTEM account. Any authenticated local Windows user can invoke the repair through the Windows Installer API or msiexec, enabling arbitrary code execution with SYSTEM privileges.

The record

CVE
CVE-2021-27766
Published
May 6, 2022
Updated
Sep 17, 2024
Vendor
HCLSoftware
Product
HCL BigFix Platform
Classifications
CWE-269, CWE-379, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.5 - 9.5.18, 10 - 10.0.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

HCLSoftware · HCL BigFix Platformversion=9.5 - 9.5.18, 10 - 10.0.5

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.7HCL SoftwareCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management
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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