# CVE-2026-9491: Synology Chat Server SSRF in webhook

Source: https://junglewise.ai/threats/cve-2026-9491-synology-chat-server-ssrf-in-webhook  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-28. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-9491 · Severity: medium · CVSS 4.3 · Published 2026-08-28

Synology Chat Server contains a server-side request forgery vulnerability in its webhook functionality that allows authenticated users to access non-sensitive internal information. An attacker with valid credentials can exploit this to probe internal network resources and bypass security controls designed to restrict outbound requests.

Technologies: [Synology Chat Server](https://junglewise.ai/threats/technologies/chat-server). Vendors: [Synology](https://junglewise.ai/threats/vendors/synology).

## Quick answers

**Is CVE-2026-9491 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-9491 being exploited in the wild.

**How severe is CVE-2026-9491?** Medium severity, with a CVSS score of 4.3, published 28 August 2026.

**Which products and versions are affected?** Synology Chat Server before 2.4.5-22148.

**Is there a fix for CVE-2026-9491?** A patch was published on 2026-05-26: Fixed in version 2.4.5-22148 or above Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-9491 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-9491?** Check whether you run Synology Chat Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This is a server-side request forgery (SSRF) vulnerability (CWE-918) in the webhook component of Synology Chat Server prior to version 2.4.5-22148. The vulnerability requires authentication and network access but no user interaction. An authenticated remote attacker can manipulate webhook requests to access or retrieve non-sensitive information from internal systems that would normally be restricted. The vulnerability has been patched in version 2.4.5-22148 and later.

## Affected products

- Synology Chat Server before 2.4.5-22148

## Timeline

- 2026-05-26: disclosed: Initial public release of Synology-SA-26:10
- 2026-08-28: disclosed: Vulnerability details disclosed
- 2026-05-26: patched: Fixed in version 2.4.5-22148 or above

## References

- [https://www.synology.com/en-global/security/advisory/Synology_SA_26_10](https://www.synology.com/en-global/security/advisory/Synology_SA_26_10)

## Related threats

- [Synology Chat Server XSS in extract domain](https://junglewise.ai/threats/cve-2026-9548-synology-chat-server-xss-in-extract-domain)
- [Synology Chat Server cross-site scripting in domain extraction](https://junglewise.ai/threats/cve-2026-40541-synology-chat-server-cross-site-scripting-in-domain-extraction)