CVE-2026-73630: siyuan-note siyuan Observable Discrepancy

Vulnerability summary

CVE-2026-73630 is a medium (CVSS 6.9) Observable Discrepancy vulnerability in siyuan-note siyuan. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 26.5% of scored vulnerabilities.

Timeline

1. 14-08-2026
   PublishedVulnerability first disclosed.
2. 17-08-2026
   Last modifiedVulnerability information updated.

Description

SiYuan before v3.7.4 contains an information disclosure vulnerability in the /api/filetree/authFilePublishAccess endpoint, which is registered with CheckAuth only and is reachable anonymously. The endpoint never sets a failure code, so its outcome is signalled entirely by the response message and by the presence of a Set-Cookie header, and these signals differ across access tiers. By submitting requests with an empty password for a candidate document identifier, an anonymous attacker can distinguish whether a document is public/nonexistent, password-protected, or exists at the hidden or forbidden tier, thereby confirming the existence of documents they are not permitted to access. Because hidden and forbidden entries store an empty password, such requests also cause the server to issue a publish-auth cookie for forbidden documents.

• CWE-203Observable DiscrepancyThe product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.