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Revenera InstallshieldApplication · Flexera

CVE-2021-41526

HIGH · 7.8 CVSS v3.1 Published 2023-03-29
Fix available
A fix is available. Upgrade to 2021 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability has been reported in the windows installer (MSI) built with InstallScript custom action. This vulnerability may allow privilege escalation when invoked ‘repair’ of the MSI which has an InstallScript custom action.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This vulnerability exists in Windows MSI installers that use InstallScript custom actions. When the MSI repair function is invoked, the InstallScript custom action runs with elevated privileges, potentially allowing an attacker to execute arbitrary code or gain privileged access through the repair operation.

MitigationReview and secure InstallScript custom actions in MSI packages to ensure they do not allow privilege escalation during repair operations; consider removing or properly sandboxing vulnerable custom actions.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Revenera InstallshieldApplication
Affected:< 2021= 2021

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify InstallShield version in use
    Check the version of Flexera Revenera InstallShield used to build or maintain your MSI installers. This can be found in the InstallShield project file (.ism) or by examining the MSI package metadata in tools such as Orca, MSI Explorer, or similar MSI analysis utilities.
    Affected if The version is 2021 or any version prior to 2021 (versions < 2021 or = 2021).
  2. Locate MSI packages with InstallScript custom actions
    Examine your MSI databases for custom actions that invoke InstallScript. Use MSI analysis tools to query the CustomAction table for actions where the Type column indicates InstallScript (typically action types 51-55 or custom action sources referencing InstallScript DLLs).
    Affected if The MSI contains any InstallScript custom actions defined in the CustomAction table.
  3. Verify repair operation is available
    Determine whether the MSI package is configured to support repair operations. Check the MSI Property table for the 'RepairPath' property or verify that the package includes the 'Reinstall' feature mode. Inspect whether the MSI is distributed in a form that allows end-users or attackers to trigger repair (via Add/Remove Programs repair button, msiexec /f command, or similar).
    Affected if The MSI supports repair operations and is accessible to users or processes that could trigger the repair function.
  4. Confirm elevated execution context during repair
    Review the InstallScript custom action definitions in the InstallExecuteSequence table. Check the scheduling and condition columns to verify whether these custom actions are set to execute with elevated privileges during repair mode. Look for msidbCustomActionTypeNoImpersonate flag or elevated execution context.
    Affected if InstallScript custom actions are scheduled to run with elevated (system) privileges during repair operations.

Your environment is affected if you use InstallShield version 2021 or earlier and have MSI packages containing InstallScript custom actions that execute with elevated privileges when the repair function is invoked.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2021 or later
Fixed in 2021
Interim mitigation

Review and secure InstallScript custom actions in MSI packages to ensure they do not allow privilege escalation during repair operations; consider removing or properly sandboxing vulnerable custom actions.

Recommended fix Moderate confidence

InstallShield 2022 or later

  1. 1. Identify all systems running Revenera InstallShield version 2021 or earlier that build MSI installers with InstallScript custom actions
  2. 2. Download InstallShield 2022 or later from the official Revenera/Flexera download portal
  3. 3. Upgrade InstallShield on all build systems to the latest stable version (2022 or subsequent release)
  4. 4. Rebuild all MSI installers that use InstallScript custom actions using the upgraded InstallShield version
  5. 5. Redistribute the rebuilt MSI installers to replace vulnerable versions
  6. 6. Verify the repair functionality works correctly in the new MSI packages
Caveat Minimal risk - standard version upgrade; verify custom InstallScript actions work as expected in rebuilt installers

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Revenera Installshield Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-41526 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data