Which versions of SiYuan are affected by CVE-2026-68587?

SiYuan, a knowledge management application, contains a critical vulnerability (CVSS 9.2) that allows unauthorized access to documents explicitly marked as restricted or publish-disabled.. A patch is available.

Is there a public PoC exploit available for CVE-2026-68587?

Yes, a public proof-of-concept exploit is available for CVE-2026-68587. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate CVE-2026-68587?

Within 24 hours, identify all SiYuan deployments within your infrastructure and audit which are internet-accessible or available to untrusted users; immediately restrict or disable access to the getHeadingDeleteTransaction, getHeadingLevelTransaction, and getHeadingInsertTransaction endpoints if mitigation firewall rules can be deployed. Within 7 days, apply the vendor-released patch by upgrading all SiYuan installations to v3.7.3 or later, prioritizing internet-exposed instances first. Within 30 days, complete a comprehensive audit of access logs and API query patterns for the three affected endpoints to identify any potential unauthorized access to restricted documents and determine whether sensitive data exposure occurred.

SiYuan CVE-2026-68587

Q: What is the CVSS score of CVE-2026-68587?

CVE-2026-68587 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: 0.2%.

EUVD-2026-52275 CRITICAL

Missing Authorization (CWE-862)

2026-08-03 VulnCheck

GHSA-69mh-gvh4-8gp7

GHSA-85xq-27m5-59m9

Authentication Bypass Information Disclosure 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

7.5 HIGH

Unauthenticated network access to publish endpoints (PR:N, AV:N, AC:L) yields disclosure of restricted content only, so C:H with I:N/A:N and scope unchanged.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/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:N/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

Analysis Generated

Aug 03, 2026 - 14:28 vuln.today

Patch available

Aug 03, 2026 - 14:02 EUVD

CVE Published

Aug 03, 2026 - 13:20 cve.org

CRITICAL 9.2

DescriptionCVE.org

SiYuan versions before v3.7.3 contain an information disclosure vulnerability in the getHeadingDeleteTransaction, getHeadingLevelTransaction, and getHeadingInsertTransaction endpoints that return rendered block DOM without publish-access checks. Anonymous readers or publish RoleReader tokens can supply a heading block ID to read full rendered content of publish-disabled documents that should be restricted.

AnalysisAI

Information disclosure in SiYuan (a personal knowledge-management/note-taking application) before v3.7.3 lets anonymous readers or low-privilege publish RoleReader tokens read the full rendered content of documents that were explicitly marked publish-disabled. The getHeadingDeleteTransaction, getHeadingLevelTransaction, and getHeadingInsertTransaction endpoints return rendered block DOM without enforcing publish-access checks, so supplying a target heading block ID leaks restricted content. Reported by VulnCheck with a vendor patch available; no public exploit identified at time of analysis, and this is not listed in CISA KEV.

Technical ContextAI

SiYuan is an open-source, block-based knowledge/note-taking platform (vendor siyuan-note, CPE cpe:2.3:a:siyuan-note:siyuan:*) that supports a 'publish' mode exposing selected documents to anonymous or role-scoped readers while keeping others private. The flaw is CWE-862 (Missing Authorization): three heading-transaction endpoints intended to compute editing operations (delete/level-change/insert around a heading block) return the rendered block DOM of the referenced content, but they never validate that the requesting session is permitted to view that block in publish mode. Because authorization is checked at the document/publish layer but not re-enforced inside these transaction endpoints, any caller who can reach the publish interface can pivot from a known heading block ID to the underlying restricted content.

RemediationAI

Vendor-released patch: upgrade to SiYuan v3.7.3 or later, which adds publish-access enforcement to the affected heading-transaction endpoints (see GHSA-69mh-gvh4-8gp7). If immediate upgrade is not possible, the most effective compensating control is to disable the publish feature entirely, which fully closes the exposure but removes anonymous/role-based document sharing; alternatively, place the SiYuan publish interface behind an authenticating reverse proxy or network ACL so only trusted, authenticated users can reach the endpoints, at the cost of breaking legitimate anonymous publish access. Revoking or tightly scoping publish RoleReader tokens and avoiding publish-disabled sensitive documents on the same exposed instance further reduces risk until patched. Refer to the vendor advisory (https://github.com/siyuan-note/siyuan/security/advisories/GHSA-69mh-gvh4-8gp7) and https://www.vulncheck.com/advisories/siyuan-before-information-disclosure-via-getheading-transaction for details.