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.
- 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
- None listed
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
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.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-54253 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54253 exists.
Sources
Also known as GHSA-3cgm-7p4g-gffj.