Description

SiYuan before v3.8.4 contains an authorization omission in the siyuan-get IPC handler that allows remote-kernel renderers to access native clipboard formats by invoking clipboardReadMathML, clipboardReadOffice, and clipboardReadWPS commands with matching plaintext. Attackers controlling remote renderer content can obtain MathML formulas, Office bytes, and WPS bytes from local clipboard during user-mediated paste operations.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.7",
  "pubDate": "2026-09-26T14:16:45.820Z",
  "pubdate": "2026-09-26T14:16:45.820Z",
  "executiveSummary": "SiYuan versions prior to 3.8.4 are susceptible to an authorization omission vulnerability within the siyuan-get IPC (Inter-Process Communication) handler.\nThe vulnerability allows unauthorized remote-kernel renderers to interact with privileged clipboard functions that should be restricted to trusted local context.\nAn attacker capable of controlling the content of a remote renderer can programmatically invoke clipboardReadMathML, clipboardReadOffice, and clipboardReadWPS commands.\nThis facilitates the unauthorized extraction of sensitive data from the user's local clipboard, specifically targeting MathML formulas, Office document bytes, and WPS document bytes.\nThe flaw stems from a failure to enforce proper access control checks during IPC message handling, allowing cross-context command execution.\nSuccessful exploitation results in the exposure of potentially confidential clipboard content, compromising user privacy and data integrity without requiring explicit user interaction beyond the initiation of a paste operation.",
  "technicalDetails": "The vulnerability resides in the IPC mechanism used by the SiYuan application, specifically within the siyuan-get handler. The application architecture employs a renderer-to-kernel communication model where the renderer process requests operations from the core application process. Due to insufficient authorization logic within this handler, the application fails to validate the origin or privilege level of the requester before processing sensitive IPC commands.\nThe vulnerable component is the IPC bridge facilitating communication between the remote-renderer and the native application kernel. Specifically, the functions 'clipboardReadMathML', 'clipboardReadOffice', and 'clipboardReadWPS' are exposed to the IPC interface without adequate gating. These functions are intended to facilitate document import and data processing; however, they provide broad access to native clipboard formats.\nThe attack flow initiates when an attacker successfully influences a remote renderer, potentially through a compromised plugin, a malicious web-view, or cross-site scripting (XSS) within a rendered document. Once execution is achieved in the renderer context, the attacker transmits a crafted IPC request to the siyuan-get handler.\nBy invoking the aforementioned clipboard read functions, the attacker bypasses the expected security boundary. The kernel process, operating with native permissions, accesses the user's system clipboard. If the clipboard contains MathML data or binary blobs formatted for Microsoft Office or WPS Office, the kernel retrieves this data and returns it to the calling renderer process, effectively exfiltrating the contents to the attacker's controlled environment.\nThis vulnerability does not require authentication within the application, as the IPC handler is inherently trusted by the native kernel. The primary requirement for exploitation is the ability to execute code within a renderer process, which acts as the 'remote-kernel renderer' context defined in the scope. The impact is significant because it grants attackers the ability to 'sniff' sensitive clipboard data that the user may have copied from external, secure applications, thereby breaking the isolation between the SiYuan application and the underlying operating system's clipboard management."
}