# CVE-2026-54253: TS3 Manager: Reflected XSS via /api/download port parameter steals operator session

> Reflected XSS in TS3 Manager allows attackers to steal operator session tokens and ServerQuery passwords, leading to account takeover.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Sep 2026
- **Updated:** 23 Sep 2026
- **Also known as:** GHSA-3cgm-7p4g-gffj

## What is CVE-2026-54253?

CVE-2026-54253 is a high-severity cross-site scripting vulnerability in joni1802 ts3-manager, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

TS3 Manager is modern web interface for maintaining Teamspeak3 servers. Prior to 2.2.6, the /api/download handler in packages/server/routes/api.js passes the attacker-controlled port query parameter to socket.connect(port, host) and returns the resulting error.message through res.status(400).send(error.message) as text/html without a Content Security Policy. When a logged-in operator follows a crafted top-level link, the reflected value executes in the manager origin. The token cookie set in packages/ui/src/store/modules/query.js lacks HttpOnly, Secure, and an explicit SameSite attribute, allowing the script to read the token and call the autofillform event in packages/server/socket.js. autofillform returns the decoded JWT, including the cleartext ServerQuery password, enabling operator-session hijacking and control of the managed TeamSpeak server when the operator uses administrative ServerQuery credentials. A valid operator session and user interaction are required. This issue is fixed in 2.2.6.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-54253?


## How do I fix CVE-2026-54253?

No fix has been published for CVE-2026-54253 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54253 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54253 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54253 and fix it if it is affected.

What it is: CVE-2026-54253 is a high-severity cross-site scripting vulnerability in joni1802 ts3-manager, published on 17 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54253 exists.

Affected product: joni1802 ts3-manager. 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-2026-54253/ (Markdown: https://insights.sbomify.com/CVE-2026-54253/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54253
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54253
- OSV: https://osv.dev/vulnerability/CVE-2026-54253

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-54253/
Summaries are generated and may contain mistakes; the official description above is the record.