dbcve.org
TeamviewerApplication

CVE-2021-34858

HIGH · 7.8 CVSS v3.1 Published 2022-01-13
Fix available
A fix is available. Upgrade to 15.21.2 or later.
See remediation →
81/100
Remediation priority · High
No privileges

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
This vulnerability allows remote attackers to execute arbitrary code on affected installations of TeamViewer. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of TVS files. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated structure. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-13606.

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 confidence

Buffer over-read vulnerability in TeamViewer when parsing TVS files. The lack of proper validation of user-supplied data allows reading past the end of an allocated structure, which can be leveraged for code execution in the context of the current process. Requires user interaction (opening malicious TVS file or visiting malicious page).

MitigationUpdate TeamViewer to the latest patched version. Avoid opening untrusted TVS files or visiting untrusted webpages until the patch is applied.

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
TeamviewerApplication
Affected:< 15.21.2

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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. Verify TeamViewer is installed
    Check for TeamViewer installation directory (Windows: C:\Program Files\TeamViewer, Linux: /opt/teamviewer, macOS: /Applications/TeamViewer.app) or search for teamviewer.exe (Windows), teamviewer (Linux), or TeamViewer.app (macOS)
    Affected if TeamViewer is present on the system
  2. Determine installed TeamViewer version
    Windows: Query registry key HKLM\SOFTWARE\TeamViewer\Version or check Version.dll in TeamViewer folder; Linux: Run 'teamviewer --version' or check /opt/teamviewer/version; macOS: Right-click TeamViewer.app > Get Info or run 'defaults read /Applications/TeamViewer.app/Contents/Info.plist CFBundleShortVersionString'
    Affected if Version is retrieved successfully
  3. Compare version to CVE threshold
    Compare the installed version number to 15.21.2 - ensure the full version string is evaluated (e.g., 15.21.1, 15.20.5, 14.x would all be vulnerable)
    Affected if Installed version is 15.21.1 or earlier, or any version with major.minor < 15.21
  4. Check for recent TVS file activity
    Review browser download folders, recent documents, or email attachments for .tvs files; examine TeamViewer connection logs (Windows: %APPDATA%\TeamViewer\, Linux/Mac: ~/.TeamViewer/) for incoming .tvs file transfers
    Affected if User has recently opened or received a TVS file from an untrusted source

User is affected if TeamViewer version is below 15.21.2 and the user opens a malicious TVS file or visits a webpage that delivers a malicious TVS file.

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 15.21.2 or later
Fixed in 15.21.2
Interim mitigation

Update TeamViewer to the latest patched version. Avoid opening untrusted TVS files or visiting untrusted webpages until the patch is applied.

Recommended fix High confidence

TeamViewer 15.21.2

  1. Check current TeamViewer version (Help > About TeamViewer in the application or run 'teamviewer --version' from command line)
  2. Navigate to the official TeamViewer download page at www.teamviewer.com
  3. Download TeamViewer version 15.21.2 or later for your platform
  4. Close any running TeamViewer instances
  5. Run the installer and follow the prompts to upgrade
  6. Restart TeamViewer after installation completes
  7. Verify the installed version is 15.21.2 or later

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

Fix this in Teamviewer Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-34858 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-34858 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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