Mistral Vibe: Permission bypass via bash line continuation
Summary
Mistral Vibe, a command-line coding assistant, contains a permission validation bypass in its bash command parser. The tool's parser (tree-sitter-bash) and the shell (bash) interpret backslash-newline line continuations differently, so an allowlisted prefix such as cd passes the permission check while a hidden command such as a curl request is executed. An attacker who can get a crafted command string into the agent's workflow, for example through untrusted repository content, can run unauthorized commands with the user's privileges. The attack requires user interaction (UI:P) and no prior privileges.
Affected
- Mistral Vibe (mistral-vibe, Python package) versions before 2.25.5
- Unaffected: 2.25.5 and later
Fixed in
- Fixed in 2.25.5 (commit c069ffa1e12fb5f2487b489217c40ab97721d553, PR #1111)
Workaround
- No workaround documented by the vendor.
- Interim measure (not from vendor): do not use auto-approval for Bash and review the tools.bash.permission setting.
- Use the tool only in trusted folders and avoid untrusted repositories until patched.
Exploitation
- CISA SSVC: exploitation none, automatable no, technical impact total.
- VulDB reports no known exploit.
- No reports of exploitation in the wild found.
Our recommendation
- Inventory all Mistral Vibe installations on developer workstations and CI runners.
- Update to at least 2.25.5, preferably the latest 3.x release.
- Until patched, disable auto-approval for Bash commands and work only in trusted repositories.
- Monitor executed shell commands of the agent for unexpected network requests.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- VulnCheck advisory www.vulncheck.com
- Mistral Vibe release v2.25.5 github.com
- Fix commit c069ffa github.com
- Pull request #1111 github.com
- OSV entry CVE-2026-109428 osv.dev
- VulDB entry 417892 vuldb.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 04:21.
Original description (NVD)
Mistral Vibe before 2.25.5 contains a permission validation bypass vulnerability that allows attackers to execute unauthorized commands by exploiting a parsing discrepancy between tree-sitter-bash and bash in handling backslash-newline line continuations in the _extract_commands() function of bash.py. Attackers can craft a command string where tree-sitter-bash extracts only an allowlisted prefix such as cd while bash joins the line continuation into a materially different and hidden command such as a curl request, causing resolve_permission to grant ALWAYS permission while bash executes unauthorized arbitrary commands.
NVD references (4)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.