CVE-2026-103762: SiYuan Information Disclosure Vulnerability

CVE-2026-103762 Overview

CVE-2026-103762 is a missing authorization vulnerability [CWE-862] in SiYuan, an open-source personal knowledge management application, affecting versions prior to v3.8.5. The flaw exists in the getRefCreateSavePath, getShorthandSavePath, and getDocCreateSavePath endpoints. These endpoints fail to validate caller privileges, allowing read-only publish visitors or anonymous users to retrieve notebook box identifiers that should remain hidden. An attacker submits a POST request containing any open notebook ID and receives the global save-box ID and the save-path template in response. This disclosure reveals the existence and creation time of unpublished notebooks that the attacker is not authorized to see.

Critical Impact
Unauthenticated or read-only publish visitors can enumerate hidden notebook identifiers and metadata, exposing information about private workspaces hosted by SiYuan publishers.

Affected Products

SiYuan versions prior to v3.8.5
SiYuan getRefCreateSavePath endpoint
SiYuan getShorthandSavePath and getDocCreateSavePath endpoints

Discovery Timeline

2026-10-02 - CVE-2026-103762 published to NVD
2026-10-06 - Last updated in NVD database

Technical Details for CVE-2026-103762

Vulnerability Analysis

SiYuan exposes several HTTP endpoints that resolve save paths for new references, shorthand notes, and documents. The resolver endpoints getRefCreateSavePath, getShorthandSavePath, and getDocCreateSavePath accept a notebook identifier in the request body and respond with the configured save-box ID and path template. In versions before v3.8.5, these handlers do not verify that the requester holds write or owner privileges for the targeted notebook. As a result, any session with publish access, including anonymous visitors on public publish instances, can query the endpoints and recover identifiers tied to unpublished notebooks. The leaked response includes the global save-box ID and the path template, which together confirm whether a hidden notebook exists and when it was created.

Root Cause

The root cause is a missing authorization check [CWE-862] in the three save-path resolver handlers. The code dispatches on the submitted notebook ID without consulting the caller's role or verifying that the notebook has been exposed through the publish configuration. Authorization enforcement that gates other write-oriented endpoints was never applied to these resolvers.

Attack Vector

An attacker with network reach to a SiYuan publish instance sends a crafted POST request to one of the three resolver endpoints with a notebook ID of interest. No credentials are required beyond publish visitor access, which may be anonymous. The JSON response confirms the notebook's existence and discloses the save-box ID and save-path template. Repeating the request across enumerated or guessed notebook IDs enables bulk discovery of hidden notebooks and their creation timestamps.

No verified proof-of-concept code is published. See the GitHub Security Advisory GHSA-2mrf-mx66-vv6g and the Vulncheck Advisory for Siyuan for additional technical context.

Detection Methods for CVE-2026-103762

Indicators of Compromise

POST requests from unauthenticated or read-only publish sessions to /api/filetree/getRefCreateSavePath, /api/filetree/getShorthandSavePath, or /api/filetree/getDocCreateSavePath.
Repeated resolver calls that iterate through different notebook ID values from the same source address, consistent with enumeration.
Resolver responses returning save-box IDs for notebooks that are not listed in the publish configuration.

Detection Strategies

Review SiYuan access logs for the three resolver endpoints and correlate caller identity with the notebook IDs returned.
Deploy a web application firewall rule that flags requests to the resolver endpoints from sessions lacking a writer role.
Baseline normal publish-visitor API usage and alert on request patterns that deviate toward filetree save-path APIs.

Monitoring Recommendations

Forward SiYuan HTTP access logs to a centralized logging platform for retention and query.
Alert on high request rates to /api/filetree/* endpoints originating from a single source over short time windows.
Track response sizes and content types for the resolver endpoints to detect scripted enumeration.

How to Mitigate CVE-2026-103762

Immediate Actions Required

Upgrade SiYuan to v3.8.5 or later on all publish and self-hosted instances.
Audit publish access configurations and disable anonymous publish visitor access where it is not required.
Rotate or review notebook IDs considered sensitive, and remove unpublished notebooks from exposed instances if they contain confidential metadata.

Patch Information

SiYuan v3.8.5 adds authorization enforcement to the getRefCreateSavePath, getShorthandSavePath, and getDocCreateSavePath endpoints. Refer to the GitHub Security Advisory GHSA-2mrf-mx66-vv6g for the official fix details and release notes.

Workarounds

Place SiYuan publish instances behind an authenticating reverse proxy that restricts access to trusted users until the upgrade is applied.
Block POST requests to the three affected endpoints at the proxy or WAF layer for sessions lacking writer privileges.
Isolate publish deployments on networks that are not reachable from untrusted sources until patched.

bash

# Example nginx snippet to block the vulnerable endpoints at the edge
location ~ ^/api/filetree/(getRefCreateSavePath|getShorthandSavePath|getDocCreateSavePath)$ {
    return 403;
}