CVE-2026-100633: Incorrect Authorization in siyuan-note siyuan
SiYuan is a self-hosted personal knowledge management system. In versions 3.8.0 through 3.8.3, the MCP file tool's sensitive-path guard (util.IsForbiddenAbsPath(), invoked from resolvePath()) is applied only to the allowed root of recursive operations and not to each resolved descendant path — an incomplete fix for GHSA-c8r8-95hg-mp34. An authenticated administrator using the in-app Agent or the external MCP server can therefore bypass the protected-workspace-file denylist: file.grep can return matching lines from non-hidden protected descendants (for example conf/conf.json, TLS keys, data/snippets/conf.json, data/templates/, data/.siyuan/publishAccess.json, notebook .siyuan internals, or the kernel log), file.copy can copy protected descendants to an ordinary path where file.read can then retrieve them, and unzip can overwrite protected descendants using ordinary, lexically contained ZIP member names. Because file.grep is globally classified as a safe action, it receives no per-call confirmation, and the confirmation cards for file.copy and unzip show only the allowed root arguments. This issue is fixed in version 3.8.4. Suggested title: SiYuan 3.8.0 through 3.8.3 Sensitive-Path Guard Bypass in Recursive MCP File Operations.
AI Analysis
Technical Summary
SiYuan, a self-hosted personal knowledge management system, has an incorrect authorization vulnerability in versions 3.8.0 through 3.8.3. The MCP file tool's sensitive-path guard function (util.IsForbiddenAbsPath()), invoked from resolvePath(), is only applied to the root path of recursive operations and not to each resolved descendant path. This incomplete fix for a previous issue (GHSA-c8r8-95hg-mp34) allows an authenticated administrator using the in-app Agent or external MCP server to bypass the protected-workspace-file denylist. Actions such as file.grep, file.copy, and unzip can be used to access or overwrite protected descendant files without proper confirmation or restrictions. The vulnerability is resolved in version 3.8.4.
Potential Impact
An authenticated administrator can bypass protections on sensitive files and directories within the workspace, potentially exposing confidential configuration files, TLS keys, internal system files, and logs. This could lead to unauthorized disclosure or modification of sensitive data within the SiYuan environment.
Mitigation Recommendations
Upgrade SiYuan to version 3.8.4 or later, where this vulnerability is fixed. No other mitigations are indicated by the vendor advisory.
CVE-2026-100633: Incorrect Authorization in siyuan-note siyuan
Description
SiYuan is a self-hosted personal knowledge management system. In versions 3.8.0 through 3.8.3, the MCP file tool's sensitive-path guard (util.IsForbiddenAbsPath(), invoked from resolvePath()) is applied only to the allowed root of recursive operations and not to each resolved descendant path — an incomplete fix for GHSA-c8r8-95hg-mp34. An authenticated administrator using the in-app Agent or the external MCP server can therefore bypass the protected-workspace-file denylist: file.grep can return matching lines from non-hidden protected descendants (for example conf/conf.json, TLS keys, data/snippets/conf.json, data/templates/, data/.siyuan/publishAccess.json, notebook .siyuan internals, or the kernel log), file.copy can copy protected descendants to an ordinary path where file.read can then retrieve them, and unzip can overwrite protected descendants using ordinary, lexically contained ZIP member names. Because file.grep is globally classified as a safe action, it receives no per-call confirmation, and the confirmation cards for file.copy and unzip show only the allowed root arguments. This issue is fixed in version 3.8.4. Suggested title: SiYuan 3.8.0 through 3.8.3 Sensitive-Path Guard Bypass in Recursive MCP File Operations.
CVSS v4.0
Score 8.5high
Affected software
siyuan-note
siyuan
pkg:github/siyuan-note/siyuanRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
SiYuan, a self-hosted personal knowledge management system, has an incorrect authorization vulnerability in versions 3.8.0 through 3.8.3. The MCP file tool's sensitive-path guard function (util.IsForbiddenAbsPath()), invoked from resolvePath(), is only applied to the root path of recursive operations and not to each resolved descendant path. This incomplete fix for a previous issue (GHSA-c8r8-95hg-mp34) allows an authenticated administrator using the in-app Agent or external MCP server to bypass the protected-workspace-file denylist. Actions such as file.grep, file.copy, and unzip can be used to access or overwrite protected descendant files without proper confirmation or restrictions. The vulnerability is resolved in version 3.8.4.
Potential Impact
An authenticated administrator can bypass protections on sensitive files and directories within the workspace, potentially exposing confidential configuration files, TLS keys, internal system files, and logs. This could lead to unauthorized disclosure or modification of sensitive data within the SiYuan environment.
Mitigation Recommendations
Upgrade SiYuan to version 3.8.4 or later, where this vulnerability is fixed. No other mitigations are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-09-26T02:31:42.100Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ab7c9a5f7a7c5410652fd1c
Added to database: 09/26/2026, 13:33:25 UTC
Last enriched: 09/26/2026, 14:04:20 UTC
Last updated: 09/27/2026, 01:57:11 UTC
Views: 11
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