SSRF in Synology Chat Server

CVE-2026-9491

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.

Vulnerability class: SSRF (Server-Side Request Forgery)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (27.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 27.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-9491: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: -0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-9491?
CVE-2026-9491 is a medium-severity vulnerability in Synology Chat Server, classified under Server-Side Request Forgery (SSRF). CVSS score: 4.3/10. Published 2026-08-28.
How severe is CVE-2026-9491?
Medium severity. CVSS v3 base score is 4.3 out of 10.