External risk intelligence

SiYuan SQL Injection via Search Embed Block Endpoint.

CVE advisorySeverity: CRITICAL (CVSS 9.9)

CVE-2026-69084

The vulnerability affects a web API endpoint in SiYuan. While often self-hosted, SiYuan is frequently deployed as a web-accessible service for knowledge management. Because the endpoint is reachable via network requests and does not require authentication under specific common configurations, the attack surface is exposed to any network-connected user.

SQL Injection

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This critical vulnerability in SiYuan software allows unauthenticated attackers to directly interact with the application's database, potentially enabling them to read and modify sensitive information stored in notebooks. The issue stems from an exposed API endpoint that passes user-supplied SQL commands directly to the database without proper validation or restrictions.

Database commands can be run by attackers.
Affects data integrity and confidentiality.
Confirm if SiYuan is deployed and exposed.

Attack Path

How an attacker could exploit the issue

An attacker can target the search functionality of SiYuan, specifically the `/api/search/searchEmbedBlock` endpoint. This endpoint is accessible either anonymously if publish authentication is disabled or by users with the RoleReader token. The vulnerability allows an attacker to inject SQL commands, potentially leading to unauthorized access and modification of data in cleartext notebooks.

Entry condition: Network access to the endpoint.
Trigger point: Sending crafted SQL to the search API.
Resulting risk: Read and modify notebook content.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, an unauthenticated attacker could leverage a SQL injection vulnerability in the search endpoint to read and modify content across all accessible cleartext notebooks. This could allow unauthorized access to sensitive information within user notebooks.

User notebook content.
Via network request to API.
Unauthorized data access and modification.

Operational Fix

Recommended remediation, mitigation, and detection steps

Application owners and platform teams are likely responsible for addressing this SQL injection vulnerability in SiYuan. The first practical move involves identifying all SiYuan instances, confirming their network exposure, and verifying if they are business-critical. Subsequently, the accountable owner should be identified to plan remediation, which may include vendor coordination for updates.

Identify and confirm accountable application owners.
Verify SiYuan instance reachability and criticality.
Plan and execute vendor-coordinated updates.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is SiYuan software?

SiYuan is a privacy-first, locally hosted knowledge management and note-taking application. It allows users to create, organize, and store information in structured notebooks. Because it often acts as a self-hosted web service for collaboration or remote access, it manages sensitive data that relies on the integrity of its internal database to keep notes private and secure.

How does CVE-2026-69084 work?

This vulnerability is a SQL injection (CWE-89) weakness. The application takes input from the search API and passes it directly to the database without filtering. This allows an attacker to manipulate the database commands, enabling them to bypass normal security controls to read or change data in cleartext notebooks.

Do I need to be authenticated to trigger this bug?

No. The vulnerable API endpoint does not require administrative privileges. It is reachable by users with a limited reader token or, if publish authentication is disabled in your settings, by any anonymous user on the network. The bug is not triggered by standard, legitimate search requests, but only when a crafted, malicious SQL statement is sent to the specific endpoint.

Is my SiYuan instance at risk?

Halo Surface Signal indicates that SiYuan instances are often deployed as web-accessible services. If your instance is reachable over the network, it is exposed to this risk. You are at higher risk if you have disabled authentication for published content, as this removes even the basic gatekeepers, allowing unauthenticated network users to reach the vulnerable endpoint directly.

What is the first step to address CVE-2026-69084?

Begin by identifying all SiYuan deployments in your environment and confirming which are accessible over the network. Once you have a list of active instances, prioritize those exposed to the internet. Since this is a software-level defect in the database handling, you must plan to update your SiYuan installation to version 3.7.3 or later to secure the search API.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.