CVE-2026-70558

Received Received - Intake

Unauthenticated Path Traversal in Dinky

Publication date: 2026-08-06

Last updated on: 2026-08-06

Assigner: VulnCheck

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-06

Last Modified

2026-08-06

Generated

2026-08-07

AI Q&A

2026-08-07

EPSS Evaluated

N/A

NVD

CVE-2026-70558

Affected Vendors & Products

Vendor	Product	Version / Range
dinky	dinky	1.2.5

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-434	The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.

Attack-Flow Graph

Executive Summary

This vulnerability allows unauthenticated attackers to write arbitrary files to the Dinky service account's writable directories by sending a specially crafted HTTP request with a hardcoded token. The application fails to validate the path parameter in the POST /download/uploadFromRsByLocal handler, enabling file writes that can overwrite critical files like application binaries or static assets.

Detection Guidance

Check if Dinky is running on port 8888 without authentication or proxy. Inspect network traffic for requests to /download/uploadFromRsByLocal with the hardcoded token efda1551-7958-4e0f-80a8-dfd107df3e38. Verify if arbitrary files are writable in /opt/dinky, especially classpath, scripts, or static assets.

Impact Analysis

An attacker could overwrite application files to execute malicious code, serve malicious JavaScript to users, or modify configuration files. This could lead to remote code execution, data theft, or unauthorized access to the system running Dinky. The impact is severe due to the ability to modify application binaries and static assets.

Mitigation Strategies

Block external access to port 8888 immediately. Remove the hardcoded token and implement proper authentication. Disable the @SaIgnore route or add path validation. Restrict write permissions on /opt/dinky to prevent file overwrites. Update to a patched version if available.

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