SiYuan up to 3.6.1 Incoming Message auth keepalive uncaught exception

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.3$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in SiYuan up to 3.6.1. This affects an unknown part of the component Incoming Message Handler. This manipulation of the argument auth keepalive causes uncaught exception. This vulnerability is registered as CVE-2026-33203. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in SiYuan up to 3.6.1 and classified as problematic. Affected by this vulnerability is an unknown functionality of the component Incoming Message Handler. The manipulation of the argument auth keepalive with an unknown input leads to a uncaught exception vulnerability. The CWE definition for the vulnerability is CWE-248. An exception is thrown from a function, but it is not caught. As an impact it is known to affect availability. The summary by CVE is:

SiYuan is a personal knowledge management system. Prior to version 3.6.2, the SiYuan kernel WebSocket server accepts unauthenticated connections when a specific "auth keepalive" query parameter is present. After connection, incoming messages are parsed using unchecked type assertions on attacker-controlled JSON. A remote attacker can send malformed messages that trigger a runtime panic, potentially crashing the kernel process and causing denial of service. Version 3.6.2 fixes the issue.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-33203 since 03/18/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 3.6.2 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
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: Uncaught exception
CWE: CWE-248
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 3.6.2

Timelineinfo

03/18/2026 CVE reserved
03/21/2026 +3 days Advisory disclosed
03/21/2026 +0 days VulDB entry created
03/27/2026 +6 days VulDB entry last update

Sourcesinfo

Advisory: GHSA-3g9h-9hp4-654v
Status: Confirmed

CVE: CVE-2026-33203 (🔒)
GCVE (CVE): GCVE-0-2026-33203
GCVE (VulDB): GCVE-100-352255

Entryinfo

Created: 03/21/2026 07:52
Updated: 03/27/2026 06:05
Changes: 03/21/2026 07:52 (64), 03/27/2026 06:05 (1)
Complete: 🔍
Cache ID: 216::103

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