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.

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)

EPSS: 0.004 (32.9th percentile) — read the EPSS interpretation.

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.

Affected products

Synology Chat Server

Weakness classification (CWE)

CWE-918 — Server-Side Request Forgery (SSRF)

References

security@synology.com (vendor-advisory)

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.