# CVE-2026-4390: TeamSpeak 3 Server Connection State Management process_resend_queue use after free

> Remote attackers can exploit a use-after-free flaw in TeamSpeak 3 Server's connection state management to potentially execute code or cause denial of service.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 May 2026
- **Updated:** 27 May 2026
- **Also known as:** GHSA-cr8m-87qj-3732

## What is CVE-2026-4390?

CVE-2026-4390 is a medium-severity use after free vulnerability in TeamSpeak 3 Server, published on 27 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A weakness has been identified in TeamSpeak 3 Server up to 3.13.7. This affects the function process_resend_queue of the component Connection State Management. This manipulation causes use after free. The attack may be initiated remotely. Upgrading to version 3.13.8 is able to mitigate this issue. The affected component should be upgraded.

Weakness: CWE-416 (Use After Free), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-4390?


## How do I fix CVE-2026-4390?

No fix has been published for CVE-2026-4390 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4390 being exploited?

There is no known exploitation of CVE-2026-4390 in the wild and no public exploit code.

Public exploit code:

- Proof-of-concept exploits for CVE-2026-4390, CVE-2026-4391 and CVE-2026-4392 in TeamSpeak 3 server (3.13.7). (github_poc): https://github.com/born0monday/teamspeak3-vulnerabilities

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4390 and fix it if it is affected.

What it is: CVE-2026-4390 is a medium-severity use after free vulnerability in TeamSpeak 3 Server, published on 27 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-4390 in the wild and no public exploit code.

Affected product: TeamSpeak 3 Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-4390/ (Markdown: https://insights.sbomify.com/CVE-2026-4390/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4390
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4390
- OSV: https://osv.dev/vulnerability/CVE-2026-4390

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4390/
Summaries are generated and may contain mistakes; the official description above is the record.