siyuan-note SiYuan up to 3.8.1 Asset Serving cross site scripting

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.2$0-$5k1.41+

Summaryinfo

A vulnerability was found in siyuan-note SiYuan up to 3.8.1. It has been declared as problematic. Affected by this vulnerability is an unknown functionality of the component Asset Serving. Executing a manipulation can lead to cross site scripting. This vulnerability appears as CVE-2026-84803. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in siyuan-note SiYuan up to 3.8.1. It has been declared as problematic. This vulnerability affects some unknown processing of the component Asset Serving. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. CVE summarizes:

SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in asset serving due to an incomplete extension blocklist that misses script-capable file types. Attackers can upload files with extensions like .xht, .ehtml, .xsl, .xbl, or .rdf that resolve to executable media types and execute JavaScript to steal API tokens and compromise workspaces.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-84803 since 09/02/2026. The exploitation appears to be easy. The attack can be initiated remotely. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 3.8.2 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.2
VulDB Meta Temp Score: 6.2

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.0
CNA Vector (VulnCheck): 🔒

CVSSv2info

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

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
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 3.8.2

Timelineinfo

09/02/2026 Advisory disclosed
09/02/2026 +0 days CVE reserved
09/02/2026 +0 days VulDB entry created
09/02/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-84803 (🔒)
GCVE (CVE): GCVE-0-2026-84803
GCVE (VulDB): GCVE-100-398068

Entryinfo

Created: 09/02/2026 13:38
Changes: 09/02/2026 13:38 (76)
Complete: 🔍
Cache ID: 216::103

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