CVE-2021-34859

Code execution via malformed TVS file parsing

Published Oct 25, 2021 · Updated Aug 4, 2024

Memory corruption in TeamViewer 15.16.8.0 allows remote attackers to execute code through a crafted TVS file opened by a user. The TVS parser does not properly validate user-supplied file data before memory operations, producing memory corruption in the current process. Exploitation requires the target to visit a malicious page or open a malicious file, and successful exploitation runs attacker-controlled code with the current process privileges.

CVSS severity7.8
High
EPSS probability8.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in TeamViewer 15.16.8.0 allows remote attackers to execute code through a crafted TVS file opened by a user. The TVS parser does not properly validate user-supplied file data before memory operations, producing memory corruption in the current process. Exploitation requires the target to visit a malicious page or open a malicious file, and successful exploitation runs attacker-controlled code with the current process privileges.

The record

CVE
CVE-2021-34859
Published
Oct 25, 2021
Updated
Aug 4, 2024
Vendor
TeamViewer
Product
TeamViewer Desktop Clients
Classifications
CWE-119, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 25, 2021CVE 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?

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

  1. Affected versionversion=15.16.8.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

TeamViewer · TeamViewer Desktop Clientsversion=15.16.8.0

Published CVSS scores

7.8Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:N/UI:R/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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1204.002Malicious File
T1203Exploitation for Client Execution

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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