Executive brief
blackms aistack is a production-grade agent orchestration platform. The web server's static file handler fails to properly validate file paths, allowing attackers to read arbitrary files from the server's filesystem outside the intended static directory. An attacker with network access can craft specially encoded path requests to retrieve sensitive files such as source code or configuration data.
Technical details
The vulnerability is a classic path traversal (CWE-22) in the static file handler component (src/web/server.ts). The server accepts req.url, joins it directly with the static directory using path.join(), and reads the resulting file with fs.readFileSync() without verifying that the normalized path remains within the static root directory. An attacker can send HTTP requests with URL-encoded traversal sequences (e.g., /..%2f..%2f..%2fpackage.json) that bypass inadequate validation to read files outside the intended directory. The attack requires only network access to the web server and knowledge of target files readable by the process. No authentication, user interaction, or special privileges are required. The vulnerability allows attackers to disclose confidential files; no patch was available at the time of the initial report.
Affected products
- blackms aistack up to 1.6.1
Timeline
- 2026-07-12: disclosed: Vulnerability disclosed via GitHub issue #57
- 2026-08-27: advisory: CVE-2026-81560 published