Which versions of SiYuan are affected by CVE-2026-72789?

SiYuan before version 3.7.4 exposes encrypted notebook content to unauthenticated internet users through the publish API, allowing any visitor to retrieve fully decrypted sensitive documents without…. A patch is available.

Is there a public PoC exploit available for CVE-2026-72789?

Yes, a public proof-of-concept exploit is available for CVE-2026-72789. Prioritise patching immediately. EPSS: 0.3%.

How to fix or mitigate CVE-2026-72789?

Within 24 hours, immediately disable or restrict access to the SiYuan publish API endpoint on all internet-facing deployments using firewall rules, VPN-only access, or application-level authentication. Within 7 days, audit encrypted notebooks for sensitive content and move critical data to offline storage while awaiting vendor remediation; notify affected stakeholders of potential exposure. Within 30 days, monitor SiYuan security advisories and vendor communications for patch availability, then plan immediate deployment of any released security update.

SiYuan CVE-2026-72789

Q: What is the CVSS score of CVE-2026-72789?

CVE-2026-72789 has a CVSS 4.0 base score of 9.2 (Critical). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.3%.

EUVD-2026-57449 CRITICAL

Missing Authorization (CWE-862)

2026-08-12 VulnCheck

GHSA-v684-q882-jgmq

GHSA-xx34-6cjg-prh8

Authentication Bypass Siyuan Siyuan Note

9.2

CVSS 4.0 · Vendor: VulnCheck

Severity by source

Vendor (VulnCheck) PRIMARY

9.2 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

8.6 HIGH

Unauthenticated network read of decrypted notes (PR:N/UI:N/AC:L); S:C reflects the authorization flaw exposing the protected encrypted subsystem; confidentiality-only (C:H, I:N/A:N).

3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Patch available

Aug 12, 2026 - 20:03 EUVD

Analysis Generated

Aug 12, 2026 - 19:55 vuln.today

CVE Published

Aug 12, 2026 - 19:07 cve.org

CRITICAL 9.2

DescriptionCVE.org

SiYuan before v3.7.4 fails to properly validate publish access for encrypted notebooks, treating them as publicly accessible by default. Anonymous readers can enumerate and retrieve fully decrypted document content from unlocked encrypted notebooks through the publish API without authentication or key material.

AnalysisAI

Anonymous information disclosure in SiYuan before v3.7.4 lets unauthenticated remote readers retrieve fully decrypted content from encrypted notebooks. Because the publish API treats encrypted notebooks as publicly accessible by default, any anonymous visitor can enumerate and read documents from an unlocked encrypted notebook without authentication or knowledge of the encryption key. Reported by VulnCheck and rated CVSS 4.0 9.2; no public exploit has been identified at time of analysis and it is not listed in CISA KEV.

Technical ContextAI

SiYuan is a self-hosted, open-source personal knowledge-management and note-taking application that supports a 'publish' mode for exposing selected content over HTTP. The root cause is CWE-862 (Missing Authorization): the publish API does not evaluate whether a notebook's encrypted/private status should restrict publish access, so it applies a permissive default that treats encrypted notebooks as publicly readable. Critically, once an encrypted notebook is unlocked in the running instance, the notebook content is available in decrypted form server-side, and the publish endpoint serves that decrypted content rather than enforcing the notebook's access controls or requiring key material. The affected package per NVD is cpe:2.3:a:siyuan-note:siyuan (all versions prior to 3.7.4).

RemediationAI

Vendor-released patch: upgrade to SiYuan v3.7.4 or later, which corrects the publish access-control check for encrypted notebooks; see GHSA-v684-q882-jgmq. Until the upgrade is applied, keep encrypted notebooks locked rather than left unlocked, since exposure occurs when an encrypted notebook is in the unlocked state. As additional compensating controls, disable the publish feature entirely if it is not required, or restrict network access to the SiYuan instance and its publish endpoint (for example bind to localhost or place it behind an authenticating reverse proxy / VPN and block direct public exposure). The trade-off is that disabling publish or restricting access removes intended sharing functionality, so scope these controls to instances that do not rely on legitimate public publishing.