What’s Vulnerable › Vulnerabilities

CVE-2021-34858

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-01-13 · updated 2026-06-17
• Weakness: CWE-125

Description

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.

Affected products

• TeamViewer: before 15.21.2 — fixed in 15.21.2

How to fix

Upgrade to a fixed version: TeamViewer 15.21.2. Check the vendor advisory for mitigations.

References

• https://community.teamviewer.com/English/discussion/117794/august-updates-security-patches/p1
• https://www.zerodayinitiative.com/advisories/ZDI-21-1001/
• https://community.teamviewer.com/English/discussion/117794/august-updates-security-patches/p1
• https://www.zerodayinitiative.com/advisories/ZDI-21-1001/

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