CVSS 4.9 MEDIUM Truy cập trái phép

SiYuan: MCP file tool's blocklist is incomplete relative to the HTTP file API it claims to align with, exposing publish-mode passwords and other sensitive workspace files

Mã khác
GHSA-c8r8-95hg-mp34
Công bố
Cập nhật
Lần đầu thấy
Nguồn
GitHub Advisory, OSV.dev

Mô tả

Summary

kernel/mcp/tools/file.go's resolvePath() includes an explicit comment stating its
sensitive-path blocklist is meant to align with the HTTP file API's established blacklist
(refuseToAccess() in kernel/api/file.go), following the remediation for GHSA-cvhv-7xhj-xjp8
("Unauthenticated Administrator takeover exfiltrated via the MCP"), which specifically
recommended restricting this tool's scope. In practice, the MCP tool implements only 1 of the
4 static blocklist entries the HTTP API enforces.

Comparison

kernel/api/file.go refuseToAccess() blocks:

  1. conf/conf.json (API token, cookie signing key, accessAuthCode)
  2. data/snippets/conf.json
  3. the entire data/templates directory
  4. data/.siyuan/publishAccess.json
  5. (dynamic, per-request) any path the current publish-mode session isn't authorized for

kernel/mcp/tools/file.go resolvePath() blocks only:

confPath := filepath.Join(util.ConfDir, "conf.json")
if abs == confPath {
    return "", fmt.Errorf("access to conf.json is forbidden")
}

Items 2, 3, and 4 are absent. The tool's own list/read/grep/find actions remain fully
functional against them.

Impact

An MCP client with access to the file tool (post-fix for GHSA-cvhv-7xhj-xjp8, i.e. a properly
authenticated Administrator-level caller) can read data/.siyuan/publishAccess.json directly:

type PublishAccessItem struct {
    ID       string `json:"id"`
    Visible  bool   `json:"visible"`
    Password string `json:"password"` // plaintext; empty string = no password
    Disable  bool   `json:"disable"`
}

This exposes the plaintext access password for every publish-mode-shared notebook/document,
letting the reader bypass password protection on any publish-mode share. This is a serious
sibling issue given the volume of publish-mode access-control bugs already reported against this
codebase — the passwords protecting exactly that feature are directly readable through a tool
whose own description says "never use for workspace data."

data/templates and data/snippets/conf.json are lower-severity but still inconsistent with
the HTTP API's own precedent for what counts as sensitive.

Why this is a distinct finding, not a duplicate

GHSA-cvhv-7xhj-xjp8 was about reachability an unauthenticated Reader-tier JWT being forwarded
to admin-scoped paths including /mcp. That has been fixed. This report is about the tool's own
scope
once reached by a legitimate, properly-authenticated caller, the remediation notes for
that same advisory explicitly called for restricting resolvePath to
WorkspaceDir/temp/siyuan/*.log, which was not implemented; instead the tool retains
workspace-wide scope with only a single-file blocklist addition.

Suggested fix

Either replicate the full refuseToAccess() blocklist in resolvePath() (minimum fix, keeps
parity with the HTTP API going forward by extracting refuseToAccess's path list into a shared
helper both call), or implement the originally-recommended allowlist restricting the tool to
WorkspaceDir/temp/siyuan/*.log for read and disabling write/delete/rename/copy entirely unless
the caller is Administrator, matching the tool's own advertised "debugging/log reading only"
scope.

Điểm và phân loại

CVSS
4.9 MEDIUM v3.1
Nguồn điểm
GitHub Advisory
Mức độ (theo nguồn)
MEDIUM
EPSS
0.39%
CWE
CWE-863

Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Ảnh hưởng

Package Bản bị ảnh hưởng Bản đã sửa
go github.com/siyuan-note/siyuan/kernel < 0.0.0-20260808051406-3542530c505f 0.0.0-20260808051406-3542530c505f

Vì sao bị lọc

  • CVSS 4.9 < 8.0 và không thuộc CISA KEV

Loại tác động

Truy cập trái phép
CWE-863

Dữ liệu riêng của nguồn

OSV.dev · ID
GHSA-c8r8-95hg-mp34

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