CVE-2026-70558
CriticalCVSS 9.8Summary
A vulnerability in Dinky allows an unauthenticated attacker to write arbitrary files on the server via the /download/uploadFromRsByLocal endpoint. Lack of path validation and a hardcoded default token enable overwriting application files and executing code as the Dinky service account.
Risk Assessment
An attacker can take control of the Dinky application by replacing executable or static files, leading to arbitrary code execution and potential full system compromise.
Recommendation
Change the default token, enforce authentication and authorization on /download/** endpoints, and restrict access to port 8888. Apply vendor updates or patches.
Original NVD description (English source)
Dinky's POST /download/uploadFromRsByLocal handler passes the caller-supplied path parameter directly to new File(path) and file.transferTo(dest) with no path validation. The route is marked @SaIgnore and /download/** is excluded from the Sa-Token interceptor, so the only guard is a header equality check against a dinkyToken value whose default (efda1551-7958-4e0f-80a8-dfd107df3e38) is hardcoded in source and shipped to every deployment. Anyone who can reach Dinky's HTTP port (8888 by default) and supplies the hardcoded token can write arbitrary files as the Dinky service account. The default Docker image runs on 8888 with no proxy or authentication and chmod 777 on /opt/dinky, so the application's own classpath, launch scripts, and static assets are writable. Demonstrated impact: overwriting /opt/dinky/config/static/index.html served attacker JavaScript to admin browsers immediately, and writing /opt/dinky/org/dinky/Dinky.class executed attacker code as the Dinky service account at the next JVM start via a classpath-shadow launched by script/bin/auto.sh. Writes are uid 9999 (flink), not root, so /etc, /root, /home, and /usr are refused. Affects Dinky v1.2.5 (the current release) and the development branch, where the code is byte-identical.