CVE-2026-73606
Received Received - Intake

SiYuan Information Disclosure via Unauthenticated Block Access

Publication date: 2026-08-13

Last updated on: 2026-08-13

Assigner: VulnCheck

Description
SiYuan versions before v3.7.4 contain an information disclosure vulnerability in the /api/block/getRefIDs endpoint that fails to check password-protected document tiers. Unauthenticated readers can discover that password-protected documents reference specific blocks and obtain block identifiers without entering the document password.

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Meta Information

Published
2026-08-13
Last Modified
2026-08-13
Generated
2026-08-13
AI Q&A
2026-08-13
EPSS Evaluated
N/A
NVD
CVE-2026-73606
EUVD
EUVD-2026-57810

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
siyuan siyuan to 3.7.4 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-639 The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

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Executive Summary

This vulnerability affects SiYuan versions before v3.7.4. It is an information disclosure issue in the /api/block/getRefIDs endpoint where unauthenticated users can discover references to password-protected documents and obtain block identifiers without entering the document password. The flaw stems from improper authorization checks, specifically failing to verify password tiers while checking document visibility.

Detection Guidance

To detect this vulnerability, monitor network traffic for requests to the /api/block/getRefIDs endpoint. Check if unauthenticated users can access block identifiers from password-protected documents. Use tools like curl to test the endpoint manually: curl -X GET 'http://<target>/api/block/getRefIDs?blockID=<target_block>' and observe if responses reveal sensitive information without authentication.

Impact Analysis

An attacker could learn if a password-protected document references a specific block and obtain block identifiers without authentication. This does not expose actual content but reveals relationships between documents, potentially aiding further attacks or reconnaissance. The impact is limited to confidentiality breaches.

Compliance Impact

This vulnerability may violate data protection regulations like GDPR and HIPAA by enabling unauthorized disclosure of document relationships and identifiers. It undermines access controls designed to protect sensitive information, potentially leading to compliance violations and increased risk of data exposure.

Mitigation Strategies

Upgrade SiYuan to version v3.7.4 or later to patch the vulnerability. If upgrading is not immediately possible, restrict access to the /api/block/getRefIDs endpoint via network-level controls or disable unauthenticated access. Review logs for suspicious requests to this endpoint and apply the official patch from the SiYuan GitHub repository.

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