CVE-2026-40541 Cross-site scripting in Synology Chat Server
Authenticated users can exploit XSS in Synology Chat Server to read/write files and cause denial of service in DSM.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-40541?
CVE-2026-40541 is a critical cross-site scripting vulnerability in Synology Chat Server, published on 28 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
An improper neutralization of input during web page generation ('Cross-site Scripting') vulnerability in extract domain in Synology Chat Server before 2.4.5-22148 allows remote authenticated users, via a UI interaction, to read or write arbitrary files and conduct denial-of-service attacks in DSM.
Weakness: CWE-79
Which versions are affected by CVE-2026-40541?
How do I fix CVE-2026-40541?
No fix has been published for CVE-2026-40541 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-2026-40541 being exploited?
There is no known exploitation of CVE-2026-40541 in the wild and no public exploit code.
Sources
Also known as GHSA-gjqh-xg93-f8cw.