SiYuan up to 3.5.9 API Endpoint appendHeadingChildren access control

CVSS Meta Temp Score
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CTI Interest Score
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6.5$0-$5k0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in SiYuan up to 3.5.9. Affected is an unknown function of the file /api/block/appendHeadingChildren of the component API Endpoint. The manipulation results in access control. This vulnerability is cataloged as CVE-2026-30926. The attack may be launched remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in SiYuan up to 3.5.9. It has been classified as critical. Affected is an unknown functionality of the file /api/block/appendHeadingChildren of the component API Endpoint. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

SiYuan is a personal knowledge management system. Prior to 3.5.10, a privilege escalation vulnerability exists in the publish service of SiYuan Note that allows low-privilege publish accounts (RoleReader) to modify notebook content via the /api/block/appendHeadingChildren API endpoint. The endpoint requires only the model.CheckAuth role, which accepts RoleReader sessions, but it does not enforce stricter checks, such as CheckAdminRole or CheckReadonly. This allows remote authenticated publish users with read-only privileges to append new blocks to existing documents, compromising the integrity of stored notes.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-30926 since 03/07/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

Upgrading to version 3.5.10 eliminates this vulnerability.

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Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.7
VulDB Meta Temp Score: 6.5

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.1
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: SiYuan 3.5.10

Timelineinfo

03/07/2026 CVE reserved
03/09/2026 +2 days Advisory disclosed
03/09/2026 +0 days VulDB entry created
03/13/2026 +4 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-30926 (🔒)
GCVE (CVE): GCVE-0-2026-30926
GCVE (VulDB): GCVE-100-349854

Entryinfo

Created: 03/09/2026 23:24
Updated: 03/13/2026 01:34
Changes: 03/09/2026 23:24 (64), 03/13/2026 01:34 (1)
Complete: 🔍
Cache ID: 216::103

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