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.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.0",
  "pubDate": "2026-08-28T08:16:40.713Z",
  "pubdate": "2026-08-28T08:16:40.713Z",
  "executiveSummary": "An improper neutralization of input during web page generation vulnerability, classified as Cross-Site Scripting (XSS), has been identified in the domain extraction functionality of Synology Chat Server versions prior to 2.4.5-22148.\nThe vulnerability allows a remote, authenticated attacker to execute malicious scripts within the context of the user's session.\nSuccessful exploitation grants the attacker the ability to perform unauthorized file read and write operations on the underlying DSM (DiskStation Manager) system and potentially trigger denial-of-service conditions.\nThis represents a significant security risk, as it bypasses standard interface controls by leveraging the trust established between the user's browser session and the Synology environment.\nExploitation requires the attacker to be authenticated to the Synology Chat Server and relies on specific UI interactions to trigger the payload execution.\nThe scope of impact extends beyond the application layer, potentially compromising system integrity and availability within the DSM ecosystem.",
  "technicalDetails": "The root cause of the vulnerability lies in the insufficient sanitization and validation of input handled by the domain extraction module within the Synology Chat Server. When the application processes domain-related metadata or user-provided input, it fails to neutralize malicious scripts, which are subsequently rendered in the DOM of the victim's browser session.\nThe vulnerable component is the domain extraction logic, which improperly processes input strings during web page generation. By injecting crafted scripts into this vector, an attacker can hijack the context of a legitimate user's session.\nThe attack flow requires the attacker to be authenticated to the Synology Chat Server. Upon authentication, the attacker interacts with the UI in a manner that forces the application to process a payload embedded within a domain string or associated input field. When a victim interacts with this maliciously crafted UI element, the embedded JavaScript is executed with the privileges of the victim's session.\nDue to the architectural integration between the Synology Chat Server and the broader DSM environment, the execution of arbitrary JavaScript within the authenticated session provides the attacker with a bridge to invoke internal APIs or perform requests that manipulate DSM resources. This capability facilitates unauthorized file system access, including reading sensitive configuration files or writing malicious content to the system.\nThe exploitation process is as follows: 1) The attacker identifies a mechanism to influence the domain extraction input processed by the chat server; 2) A payload is injected, structured to bypass any existing client-side filters; 3) The malicious input is stored or reflected by the server; 4) A target user triggers the vulnerability through a specific UI interaction; 5) The browser executes the payload, which makes asynchronous requests to DSM backend functions to read or write files; 6) The attack may also trigger abnormal application state transitions, leading to a denial-of-service condition within the DSM service environment.\nThe affected versions include all Synology Chat Server deployments prior to 2.4.5-22148. The vulnerability is highly dependent on the browser's interpretation of the unsanitized input, making it a classic stored or reflected XSS vector repurposed for elevated system-level impact."
}