CVE-2026-40541

Critical

Description

An improper neutralization of input during web page generation ('Cross-site Scripting') vulnerability in extract domain in Synology Chat Server before 2.4.5-22148 allows remote authenticated users, via a UI interaction, to read or write arbitrary files and conduct denial-of-service attacks in DSM.

SeverityCritical

CVSS9.0

Exploit probability—

ProductSynology Chat Server

PublishedAug 28, 2026

First seenAug 28, 2026

Weakness typeCWE-79Cross-site scripting (XSS)

How to fix

Update

Synology Synology Chat Server2.4.5-22148 or later

Vendor advisories

synology.com/en-global/security/advisory/Synology_SA_26_10

Affected products

Product	Affected versions	Fixed in
Synology Synology Chat Server	v < 2.4.5-22148	2.4.5-22148

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