Attack Chain

1. The attacker crafts a malicious ZIP archive containing a specially crafted skill file.
2. The filenames within the ZIP archive include path traversal sequences such as ../.
3. The attacker uploads the malicious ZIP archive to the prompts.chat application.
4. prompts.chat processes the uploaded ZIP archive without properly sanitizing the filenames.
5. The application extracts the contents of the ZIP archive, writing files to locations specified in the malicious filenames.
6. Path traversal sequences in the filenames allow the attacker to write files outside the intended extraction directory.
7. The attacker overwrites shell initialization files (e.g., .bashrc, .profile, .bash_profile) or other executable files.
8. When a user logs in or a new shell is spawned, the overwritten initialization file executes malicious code, granting the attacker arbitrary code execution on the system.

Impact

Successful exploitation of CVE-2026-22661 allows an attacker to write arbitrary files to the client system, leading to potential overwrite of sensitive system files and arbitrary code execution. The vulnerability affects systems running vulnerable versions of prompts.chat. The impact includes complete compromise of the system, data theft, and further propagation of malicious activities.

Recommendation

• Apply the patch by upgrading to commit 0f8d4c3 or later to remediate CVE-2026-22661.
• Implement server-side filename validation and sanitization to prevent path traversal attacks when handling ZIP archives within prompts.chat.
• Deploy the Sigma rules provided in this brief to your SIEM to detect potential exploitation attempts.
• Monitor web server logs for suspicious requests containing path traversal sequences in filenames as identified by the provided rules.