Executive brief
louisho5 picobot is a lightweight self-hosted bot. A security flaw in its workspace handler allows an authorized user to bypass intended file access restrictions. By creating specially crafted file links, an attacker can read or overwrite sensitive files on the host system that are outside of the bot's designated workspace, potentially leading to data theft or system corruption.
Technical details
A 'Link Following' vulnerability (CWE-59) exists in the Workspace Handler of louisho5 picobot up to 0.2.0. The flaw is located in the CreateSkill and GetSkill functions within internal/agent/tools/filesystem.go and internal/agent/tools/skill.go. While the application attempts to root file operations within a workspace directory, it fails to validate if the target file is a hardlink pointing to a location outside that root. An authenticated attacker can use the 'exec' tool to create a hardlink inside the workspace pointing to an external file, then use the filesystem or skill tools to read or overwrite that external file. This attack can be performed remotely by any user with permission to interact with the bot's tool-dispatch path. As of the advisory date, no patch has been released by the maintainer.
Affected products
- louisho5 picobot up to 0.2.0
Timeline
- 2026-07-14: advisory: NVD publication date
- 2026-07-14: disclosed: Public disclosure of the exploit and vulnerability details