CVE-2026-9491 Server-side request forgery in Synology Chat Server
Remote authenticated users can exploit an SSRF vulnerability in Synology Chat Server webhooks to obtain non-sensitive information.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-9491?
CVE-2026-9491 is a medium-severity server-side request forgery vulnerability in Synology Chat Server, published on 28 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A server-ide request forgery (SSRF) vulnerability in webhook in Synology Chat Server before 2.4.5-22148 allows remote authenticated users to obtain non-sensitive information.
Weakness: CWE-918
Which versions are affected by CVE-2026-9491?
How do I fix CVE-2026-9491?
No fix has been published for CVE-2026-9491 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-9491 being exploited?
There is no known exploitation of CVE-2026-9491 in the wild and no public exploit code.
Sources
Also known as GHSA-w5gw-c597-vxvj.