CVE-2026-9491Network attack vector

Authenticated information disclosure via webhook SSRF

Published Aug 28, 2026 · Updated Aug 28, 2026

SSRF in the webhook feature of Synology Chat Server before 2.4.5-22148 allows remote authenticated users to obtain non-sensitive information. Synology identifies the webhook as the locus but has not disclosed the affected endpoint, request construction, or missing destination validation. A valid Chat Server account is required, and the reported consequence is limited to disclosure of non-sensitive information.

CVSS severity4.3
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in the webhook feature of Synology Chat Server before 2.4.5-22148 allows remote authenticated users to obtain non-sensitive information. Synology identifies the webhook as the locus but has not disclosed the affected endpoint, request construction, or missing destination validation. A valid Chat Server account is required, and the reported consequence is limited to disclosure of non-sensitive information.

The record

CVE
CVE-2026-9491
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
Synology
Product
Synology Chat Server
Classifications
CWE-918
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <2.4.5-22148

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Synology · Synology Chat Serverversion=* <2.4.5-22148

Published CVSS scores

4.3SynologyCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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