Which versions of SiYuan are affected by CVE-2026-72793?

SiYuan self-hosted deployments before v3.7.4 expose critical authentication credentials to unauthenticated users directly via an API endpoint, allowing attackers to forge admin accounts and steal all…. A patch is available.

Is there a public PoC exploit available for CVE-2026-72793?

Yes, a public proof-of-concept exploit is available for CVE-2026-72793. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate CVE-2026-72793?

Within 24 hours: identify all SiYuan deployments and assess network exposure; block /api/system/getConf requests at network perimeter if publicly accessible. Within 7 days: disable anonymous and publish-reader user access if operationally feasible, or implement strict network-layer controls (VPN or firewall allowlist) restricting access to trusted sources only. Within 30 days: upgrade to SiYuan v3.7.4 or later when available, validate the patch eliminates the vulnerability, rotate all session signing keys and encrypted notebook key material, and conduct penetration testing to confirm effectiveness.

SiYuan CVE-2026-72793

Q: What is the CVSS score of CVE-2026-72793?

CVE-2026-72793 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-2026-57453 CRITICAL

Insufficiently Protected Credentials (CWE-522)

2026-08-12 VulnCheck

GHSA-2qqv-3jgq-vpm9

GHSA-h4v5-crx2-3cv4

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

9.3 CRITICAL

Unauthenticated network endpoint (AV:N/AC:L/PR:N/UI:N) leaks credentials (C:H); leaked signing key enables cross-account cookie forgery, a scope change (S:C) with limited integrity impact (I:L).

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/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 versions before v3.7.4 fail to mask sensitive configuration fields in the /api/system/getConf endpoint, allowing anonymous or publish-reader users to obtain the session-cookie signing key, OS username via pandoc path, and encrypted-notebook key material. Attackers can forge and tamper with session cookies to impersonate users, and on instances without access-auth codes configured, escalate to administrator privileges.

AnalysisAI

Sensitive credential exposure in SiYuan (self-hosted note-taking app) before v3.7.4 allows anonymous or publish-reader users to query the /api/system/getConf endpoint and retrieve unmasked secrets, including the session-cookie signing key, the OS username (leaked via the pandoc path), and encrypted-notebook key material. With the signing key, attackers forge and tamper with session cookies to impersonate any user, and on instances that have not configured an access-auth code they can escalate to full administrator privileges. No public exploit identified at time of analysis, but the flaw is remotely reachable without authentication against default configurations.

Technical ContextAI

SiYuan is an open-source, self-hostable personal knowledge-management/note-taking application (vendor siyuan-note, CPE cpe:2.3:a:siyuan-note:siyuan). The vulnerability maps to CWE-522 (Insufficiently Protected Credentials): the /api/system/getConf configuration endpoint returns the server configuration object without masking secret fields before serialization. Because the returned data includes the HMAC/signing key used for session cookies, the OS-level username embedded in the pandoc executable path, and key material for encrypted notebooks, disclosure of the signing key breaks the integrity guarantee of the cookie mechanism - an attacker who knows the key can mint or alter cookies that the server will accept as legitimate, turning an information-disclosure bug into an authentication-bypass and privilege-escalation primitive.

RemediationAI

Vendor-released patch: upgrade to SiYuan v3.7.4 or later, which masks the sensitive configuration fields returned by /api/system/getConf; see the advisory at https://github.com/siyuan-note/siyuan/security/advisories/GHSA-h4v5-crx2-3cv4. If immediate patching is not possible, configure an access-auth code on the instance to block anonymous access and prevent the anonymous-to-administrator escalation path (trade-off: this requires all legitimate users to authenticate and may break unauthenticated publish/read-only sharing workflows), and restrict network exposure of the SiYuan endpoint by binding it to localhost or placing it behind a VPN/reverse proxy that requires authentication or blocks /api/system/getConf. After upgrading, rotate the exposed secrets - regenerate the session-cookie signing key (invalidating existing sessions) and re-key any encrypted notebooks - since disclosed key material remains usable until rotated.