SiYuan: Missing publish-access filter on getFileAnnotation discloses private PDF annotations of forbidden/protected documents (publish mode)

CVE: This vulnerability corresponds to CVE-2026-72808.

Summary

The /api/asset/getFileAnnotation endpoint returns the content of .sya PDF-annotation files with no publish-access check. It is gated by CheckAuth only, so it is reachable by the publish RoleReader token and by the anonymous account when Publish.Auth.Enable is false. Its sibling, the /assets/* asset route does enforce publish access, including the publish password. An anonymous reader who knows an asset path can therefore read the private PDF annotations (highlights, notes) attached to assets in publish-forbidden, password-protected, or unpublished documents.

Details

getFileAnnotation resolves the annotation file via GetAssetAbsPathInBox (no path traversal) and returns the .sya content. Unlike the /assets/* route, which applies the publish-access filter including password enforcement before serving asset bytes, getFileAnnotation applies no publish-access, publish-ignore, or password check. The guarded-sibling asymmetry indicates the boundary is meant to apply to this data and was omitted here.

.sya files for encrypted-box assets are fail-closed and not exposed. The gap is limited to non-encrypted assets.

Route / auth tier. getFileAnnotation is registered CheckAuth-only. CheckAuth admits RoleReader; the publish proxy forwards port-6808 traffic with a Reader JWT (anonymous when publish auth is disabled).

Proof of Concept

Reproduced on a local instance (publish mode on 6808, Basic Auth off).

Setup (admin, 6806):

1. createNotebook{name:"AnnotPoc"} → box
2. createDocWithMd{notebook, path:"/annot-victim", markdown:"doc with a pdf"} → doc
3. POST /api/asset/upload (multipart id=<doc>, file[]=@secret.pdf) → assets/secret-...pdf
4. setFileAnnotation{path:"<asset>.sya", data:"{annotSecret:ANNOT_SECRET_4471,note:private highlight}"}
5. setPublishAccess{id:<doc>, visible:false, password:"", disable:true} → doc forbidden

Exploit (anonymous reader, 6808, no token):

POST http://127.0.0.1:6808/api/asset/getFileAnnotation
{"path":"assets/secret-...pdf.sya"}

Returns:

{"code":0,"data":{"data":"{\"annotSecret\":\"ANNOT_SECRET_4471\",\"note\":\"private highlight\"}"}}

The annotation content of a publish-forbidden document is returned to an anonymous reader with no publish-access check, while the /assets/* route serving the same asset class enforces publish access and password.

Impact

An anonymous reader (publish mode with auth disabled) or any publish RoleReader can read the private PDF annotations (highlights and notes) of assets belonging to publish-forbidden, password-protected, or unpublished documents, given the asset path. This defeats the publish-access/password boundary for annotation data. Scope is limited to annotated PDFs in non-encrypted notebooks; encrypted-box annotations are not exposed. Confidentiality-only.

Suggested fix

Apply the same publish-access check the /assets/* route uses to getFileAnnotation resolve the asset's owning document and enforce the publish-access/publish-ignore / password check before returning .sya content.