CVE-2026-72788: SiYuan Information Disclosure Flaw

CVE-2026-72788 Overview

CVE-2026-72788 is an information disclosure vulnerability in SiYuan, a personal knowledge management application. Versions before v3.7.4 fail to restrict administrator workspace state from publish readers through the UILayout filter. Unauthenticated attackers can call the getConf endpoint without authentication and retrieve sensitive administrator data. Exposed information includes open documents, search terms, notebook paths, and private asset locations. The weakness maps to CWE-863: Incorrect Authorization and is reachable over the network without user interaction.

Critical Impact
Remote unauthenticated attackers can enumerate administrator workspace metadata, including document titles, search queries, and file system paths, enabling reconnaissance for follow-on attacks.

Affected Products

SiYuan versions prior to v3.7.4
SiYuan instances exposing the publish reader interface to untrusted networks
Self-hosted SiYuan deployments with the getConf endpoint reachable

Discovery Timeline

2026-08-12 - CVE-2026-72788 published to NVD
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2026-72788

Vulnerability Analysis

SiYuan supports a publish reader mode that permits limited public access to workspace content. The UILayout filter is responsible for stripping administrator-only state from responses served to publish readers. In versions before v3.7.4, the filter does not properly enforce that authorization boundary. The getConf endpoint returns the full workspace configuration object to any caller, including unauthenticated clients. That object contains administrator UI state such as currently open documents, recent search terms, notebook paths on disk, and asset locations that should never leave the trusted context.

Root Cause

The root cause is an authorization flaw in how the UILayout filter distinguishes administrator sessions from publish reader sessions. The filter fails to redact sensitive fields before returning the configuration payload. Because the getConf endpoint does not require authentication, the incomplete filter becomes the only barrier, and its bypass produces direct data exposure. This matches the pattern described by CWE-863, where the application performs an authorization check but the decision does not correctly enforce the intended policy.

Attack Vector

An attacker sends an unauthenticated HTTP request to the getConf endpoint of a reachable SiYuan instance. The server responds with the administrator workspace configuration, which the attacker parses to extract document titles, search history, and file paths. No credentials, tokens, or user interaction are required. See the GitHub Security Advisory GHSA-hgfg-j9pg-43xw and the VulnCheck advisory on SiYuan for technical details.

Detection Methods for CVE-2026-72788

Indicators of Compromise

Unauthenticated HTTP requests to the /api/system/getConf endpoint from external IP addresses
Repeated getConf requests followed by requests targeting exposed notebook or asset paths
Access log entries lacking session cookies or authorization headers but receiving 200 OK responses

Detection Strategies

Inspect SiYuan HTTP access logs for getConf calls originating outside expected administrator IP ranges
Correlate response sizes on getConf to identify full configuration payloads leaving the server
Alert on sequential access patterns where reconnaissance of getConf is followed by direct requests to leaked asset paths

Monitoring Recommendations

Forward SiYuan web server logs to a centralized analytics platform and retain them for at least 90 days
Baseline normal administrator traffic to getConf so anomalous unauthenticated access surfaces quickly
Monitor egress traffic for bulk downloads of files whose paths match those exposed by the configuration endpoint

How to Mitigate CVE-2026-72788

Immediate Actions Required

Upgrade SiYuan to version v3.7.4 or later on all workspaces, including publish reader deployments
Restrict network exposure of SiYuan instances to trusted networks or place them behind an authenticating reverse proxy
Review recent access logs for unauthenticated getConf calls and treat any hits as reconnaissance events

Patch Information

The vendor addressed the flaw in SiYuan v3.7.4. The fix strengthens the UILayout filter so that administrator workspace state is not returned to publish reader or unauthenticated callers. Full remediation details are published in the GitHub Security Advisory GHSA-hgfg-j9pg-43xw.

Workarounds

Block external access to the getConf endpoint at a reverse proxy or web application firewall until the upgrade is applied
Disable publish reader mode on instances that do not require public sharing
Require authentication for all SiYuan endpoints by fronting the service with an identity-aware proxy

bash

# Example nginx rule to block unauthenticated access to the vulnerable endpoint
location /api/system/getConf {
    allow 10.0.0.0/8;
    deny all;
}