Description

SiYuan before v3.7.4 contains an information disclosure vulnerability in the local storage filter that returns the administrator's entire storage map with only three keys sanitized. Unauthenticated attackers or publish readers can retrieve closed-tab history, search keywords, private document identifiers, and expanded folder paths by calling the getLocalStorage endpoint.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.8",
  "pubDate": "2026-08-13T12:17:25.607Z",
  "pubdate": "2026-08-13T12:17:25.607Z",
  "executiveSummary": "SiYuan before v3.7.4 suffers from an information disclosure vulnerability residing within its local storage filtering mechanism. The flaw stems from inadequate sanitization during API calls to the getLocalStorage endpoint, which improperly returns the administrator's complete storage map while inadequately filtering only three designated keys. This architectural oversight exposes sensitive internal application state data to unauthorized parties.\nThe impact of this vulnerability encompasses the unauthorized extraction of confidential user and system data, including closed-tab history, historical search keywords, private document identifiers, and expanded folder structural paths. Such intelligence allows threat actors to map out internal repository contents and user activity.\nThe vulnerability affects SiYuan versions prior to v3.7.4. Exploitation requirements are minimal, allowing unauthenticated attackers or low-privileged publish readers to successfully invoke the vulnerable endpoint and harvest sensitive storage parameters without prior authentication or elevated privileges.",
  "technicalDetails": "The root cause of the vulnerability lies within the local storage filter implementation of SiYuan before v3.7.4. When processing requests directed at the getLocalStorage endpoint, the backend filter logic fails to comprehensively sanitize the internal storage map. Instead of applying strict allow-listing or robust attribute-level filtering across all stored keys, the mechanism improperly relies on a superficial filter that only targets and sanitizes three specific keys, leaving the remainder of the administrator storage map entirely exposed.\nThe attack vector is network-based, targeting the application interface exposed by SiYuan instances. The vulnerable component is the local storage management subsystem, specifically handling API requests that retrieve client or server-side local storage states. Because the endpoint lacks adequate access control validation and rigorous parameter sanitization, unauthorized entities can directly query the interface.\nThe step-by-step attack flow proceeds as follows: First, an unauthenticated attacker or a user with restricted publish reader privileges initiates an HTTP request targeting the getLocalStorage endpoint of the SiYuan application. Second, the application receives the request and invokes the flawed local storage filter. Third, rather than restricting access based on session privileges or sanitizing the comprehensive data structure, the filter bypasses deep inspection, masking only three pre-defined keys while serializing the rest of the administrator storage map into the response payload. Fourth, the server returns the complete storage dictionary to the caller. Finally, the attacker parses the received JSON or data stream to extract sensitive intelligence, such as closed-tab history, search keywords, private document identifiers, and expanded folder paths.\nThe post-exploitation impact includes the aggregation of reconnaissance data which can facilitate targeted follow-up attacks. By possessing private document identifiers and folder structures, an attacker gains deep insight into the internal taxonomy and sensitive contents of the victim's knowledge base."
}