CVE-2026-109429: Mistral Vibe < 2.25.4 Bash Permission Bypass via ${var@P} Prompt-Transform
Mistral Vibe before 2.25.4 contains a command permission gate bypass vulnerability that allows attackers to execute arbitrary commands by hiding a command substitution inside a single-quoted variable value that tree-sitter-bash static parsing cannot detect. Attackers can craft input such as embedding a command substitution within a single-quoted variable and re-expanding it with the ${var@P} prompt-transform operator so bash's promptvars feature executes the hidden command at runtime while only the trailing allowlisted command is classified, resulting in silent arbitrary command execution with the privileges of the agent's terminal session.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
Users of Mistral Vibe versions before 2.25.4 are exposed when the agent processes attacker-crafted input that reaches its Bash command permission gate. Successful exploitation runs commands with the privileges of the agent's terminal session.
What does an attacker need to exploit it?
An attacker needs to supply crafted Bash content containing a command substitution hidden in a single-quoted variable value and then re-expanded with the ${var@P} prompt-transform operator. The permission gate may classify only a trailing allowlisted command while Bash executes the hidden command at runtime.
Are user interaction and authentication required?
The published vector indicates network reachability, low attack complexity, no privileges required, and user interaction required. The provided data does not specify the exact user action involved.
What should be done if patching cannot happen immediately?
The provided data identifies version 2.25.4 as the fixed release. No interim mitigation or configuration workaround is provided.