SiYuan up to 3.8.3 exportBrowserHTML endpoint index.html folder path traversal

Summaryinfo

A vulnerability was found in SiYuan up to 3.8.3. It has been rated as problematic. This vulnerability affects unknown code of the file index.html of the component exportBrowserHTML endpoint. Performing a manipulation of the argument folder results in path traversal. This vulnerability is known as CVE-2026-100636. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, was found in SiYuan up to 3.8.3. This affects an unknown function of the file index.html of the component exportBrowserHTML endpoint. The manipulation of the argument folder with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. This is going to have an impact on integrity, and availability. The summary by CVE is:

SiYuan versions before v3.8.4 contain a path traversal vulnerability in the exportBrowserHTML endpoint that allows authenticated administrators to write arbitrary HTML content to index.html outside the workspace directory. Attackers can supply a folder parameter with directory traversal sequences to escape the export directory and overwrite index.html in any pre-existing kernel-writable location, enabling stored XSS or workspace defacement.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-100636 since 09/26/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The exploitation requires an enhanced level of successful authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

By approaching the search of inurl:index.html it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 3.8.4 eliminates this vulnerability.

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Productinfo

Name

• SiYuan

Version

• 3.8.0
• 3.8.1
• 3.8.2
• 3.8.3

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CPE 2.2info

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