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CVE-2026-4390 TeamSpeak CVE debrief

A use-after-free vulnerability exists in TeamSpeak 3 Server versions up to and including 3.13.7. The flaw resides in the `process_resend_queue` function within the Connection State Management component. Remote attackers can trigger this memory safety issue, potentially leading to denial of service or limited integrity/availability impacts. The vulnerability is remotely exploitable without user interaction. TeamSpeak has released version 3.13.8 to address this issue. The vulnerability was disclosed on May 27, 2026, with coordinated disclosure involving modzero and TeamSpeak Services.

Vendor
TeamSpeak
Product
TeamSpeak 3 Server
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-27
Original CVE updated
2026-05-27
Advisory published
2026-05-27
Advisory updated
2026-05-27

Who should care

Organizations operating TeamSpeak 3 Server infrastructure for voice communications, gaming communities, enterprise collaboration, or customer support channels. System administrators responsible for voice server maintenance and security patching.

Technical summary

The vulnerability exists in the `process_resend_queue` function of TeamSpeak 3 Server's Connection State Management component. A use-after-free condition can be triggered remotely, allowing attackers to manipulate freed memory. The CVSS 4.0 score of 5.3 (Medium) reflects network accessibility with low complexity but limited confidentiality impact. The attack requires low privileges and no user interaction. Memory corruption vulnerabilities of this class can potentially lead to denial of service, information disclosure, or in severe cases, code execution, though the specific impact scope here is constrained by the vulnerability's characteristics.

Defensive priority

medium

Recommended defensive actions

  • Upgrade TeamSpeak 3 Server to version 3.13.8 or later
  • Review server logs for anomalous connection patterns that may indicate exploitation attempts
  • Restrict network access to TeamSpeak server management interfaces where possible
  • Monitor for additional security advisories from TeamSpeak Services

Evidence notes

Vulnerability confirmed through official TeamSpeak security advisory (TS-SA-2026-001) and independent researcher analysis from modzero. CVSS 4.0 vector indicates network attack vector with low attack complexity, low privileges required, and no user interaction needed. CWE-416 (Use After Free) and CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) identified as underlying weaknesses.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-4390 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-4390

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-4390 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-4390

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.