go-shiori vulnerabilities and threats

go-shiori's DownloadBookmark (internal/core/download.go) fetches a caller-supplied bookmark URL using a plain http.Client with no custom DialContext or destination-IP validation (no IsLoopback, IsPrivate, IsUnspecified, or IsLinkLocalUnicast checks).

Shiori's CheckToken function (internal/domains/auth.go) validates only the JWT's HMAC signature and returns the embedded claims.Account object unmodified, never re-fetching the account from the database. No session store or token-revocation mechanism exists in the codebase.

Shiori contains a privilege escalation vulnerability in the account update endpoint that allows authenticated users to modify the owner field without authorization checks. Attackers can escalate to administrator by submitting a crafted PATCH request with owner: true, then re-authenticate to obtain an admin JWT token granting full system access.