CVE-2026-72801 in SiYuan
Summary
by MITRE • 08/12/2026
SiYuan versions before v3.7.4 disclose encrypted-notebook key-derivation material and wrapped data keys through unauthenticated endpoints in publish mode. Attackers can retrieve Argon2id salt, cost parameters, password verifiers, and wrapped notebook keys to perform unlimited offline master-password cracking without rate limiting.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability affects SiYuan note-taking software prior to version 3.7.4 and represents a critical security flaw in the application's encryption key management implementation. The issue stems from unauthenticated endpoints that expose sensitive cryptographic material necessary for decrypting encrypted notebooks. Attackers can access the Argon2id salt, cost parameters, password verifiers, and wrapped data keys through publish mode without requiring authentication, fundamentally undermining the security model of the application.
The technical flaw manifests in the improper handling of cryptographic materials within the application's publish mode functionality. When SiYuan operates in publish mode, it exposes endpoints that should remain protected and authenticated, allowing unauthorized access to key derivation parameters and wrapped encryption keys. This design oversight creates an attack surface where adversaries can obtain all necessary components for conducting offline password cracking attacks against master passwords. The exposed Argon2id parameters include the salt values, memory cost, time cost, and parallelism factors that are essential for reproducing the key derivation function.
The operational impact of this vulnerability is severe and far-reaching for users of SiYuan note-taking software. Attackers can leverage the exposed cryptographic materials to perform unlimited offline password cracking attempts without encountering rate limiting mechanisms that would normally prevent such attacks. This capability enables brute force, dictionary, and rainbow table attacks against master passwords with no practical barriers to success. The vulnerability essentially transforms what should be a secure encrypted storage system into an open target for credential compromise, potentially exposing all user data stored within the encrypted notebooks.
The security implications extend beyond simple credential theft, as this vulnerability aligns with multiple ATT&CK techniques including credential access through password cracking and privilege escalation via compromised encryption keys. From a CWE perspective, this represents a weakness in cryptographic key management and improper restriction of authenticated users, specifically CWE-320 and CWE-259. The vulnerability also demonstrates poor separation of concerns between authentication and data protection mechanisms within the application's architecture.
Organizations and individual users should immediately upgrade to SiYuan version 3.7.4 or later to address this critical flaw. The recommended mitigations include implementing proper authentication controls for all endpoints that handle cryptographic materials, introducing rate limiting and account lockout mechanisms for password verification attempts, and ensuring that encryption key derivation parameters are not exposed through unauthenticated interfaces. Additionally, system administrators should conduct thorough security assessments of other applications that may be exposing similar cryptographic material through public interfaces to prevent similar vulnerabilities from being exploited in broader network environments.