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

Status: published. Published: 2026-10-13. Updated: 2026-11-08.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/mistralai/mistral-vibe/releases/tag/v2.25.4
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/mistralai/mistral-vibe/pull/1084
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/mistralai/mistral-vibe/commit/19b5b74faa78d0816b8d4d4c7d7543fc3520678c

## Affected products and versions

- mistralai / mistral-vibe (mistralai/mistral-vibe): ≥ 0; < 2.25.4 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.7 (high); 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; source: CNA: VulnCheck

- CVSS 3.1: 8.8 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: 0.56% as of 2026-11-08; percentile 46.98%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-436

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/mistralai/mistral-vibe/releases/tag/v2.25.4 (CNA: VulnCheck; release-notes, patch)

- https://github.com/mistralai/mistral-vibe/pull/1084 (CNA: VulnCheck; issue-tracking, patch)

- https://github.com/mistralai/mistral-vibe/commit/19b5b74faa78d0816b8d4d4c7d7543fc3520678c (CNA: VulnCheck; patch, issue-tracking)

- https://www.vulncheck.com/advisories/mistral-vibe-bash-permission-bypass-via-var-p-prompt-transform (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-109429; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-109429; retrieved 2026-11-08; source updated Not reported

Revision: d0b0253c5d792c87514b6acb3ca12429d40460ce1a6e51de29e0ac8f3b72ccd4

Canonical: https://y2.dev/cve/CVE-2026-109429

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