CVE-2020-27172
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 · uneditedAn issue was discovered in G-Data before 25.5.9.25 using Symbolic links, it is possible to abuse the infected-file restore mechanism to achieve arbitrary write that leads to elevation of privileges.
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 · high confidenceA symlink attack in G-Data antivirus allows local users to abuse the infected-file restore mechanism to achieve arbitrary file write operations, leading to privilege escalation from low-privilege user to SYSTEM. The vulnerability stems from insufficient validation during the restore process.
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< 25.5.9.25CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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 checksWork through these to decide whether this CVE applies to you.
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Verify G Data Antivirus is installedCheck for G Data installation via registry key at HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\GData or look for G Data program files in C:\Program Files\G DataAffected if G Data Antivirus is present on the system
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Determine installed G Data versionOpen the G Data GUI and navigate to Help > About, or check the registry value DisplayVersion under the uninstall key found in step 1Affected if Installed version is earlier than 25.5.9.25
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Confirm restore functionality is accessibleCheck if the infected-file restore feature is enabled by examining G Data configuration files in the program directory or checking user permissions to access the quarantine/restore featureAffected if Users with low privileges can access the restore mechanism
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Inspect temp directories for suspicious symlinksExamine the Windows temp directory (typically %TEMP% or C:\Users\<username>\AppData\Local\Temp) and the G Data quarantine folder for any newly created symbolic links or unusual files with .lnk or symlink attributesAffected if Unexpected symlink files exist in temp directories used by the antivirus restore process
System is affected if G Data Antivirus is installed with a version lower than 25.5.9.25 and low-privilege users have access to the restore functionality.
Generated from the published advisory. Verify against your own configuration.
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 · scoped25.5.9.25
Apply vendor patch G-Data 25.5.9.25 or later. Restrict user access to the restore functionality and monitor for suspicious symlink creation in temp directories used by the antivirus.
25.5.9.25 or later (any version >= 25.5.9.25)
- Ensure you have a complete backup of important data before beginning the upgrade process
- Navigate to the official G Data website and download the latest version (25.5.9.25 or later) from the official download page
- If possible, uninstall the current G Data antivirus version through Windows Control Panel > Programs and Features
- Restart your system after uninstallation to ensure all previous components are cleared
- Run the installer for the new G Data version 25.5.9.25 or later with administrator privileges
- Follow the on-screen installation prompts to complete the installation
- After installation, verify the installed version matches 25.5.9.25 or newer by checking About/Version information in the G Data interface
- Restart the system to ensure all services load with the updated version
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-27172 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-27172 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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