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Mistral Vibe EUVDEUVD-2026-76122

| CVE-2026-87987 CRITICAL
External Control of System or Configuration Setting (CWE-15)
2026-09-11 HiddenLayer GHSA-r6r3-x5p3-g7m8
10.0
CVSS 4.0 · Vendor: HiddenLayer
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Plant attacker-controlled content for agent
  2. Delivery
    Induce agent to propose env-prefixed command
  3. Exploit
    Allowlist checks only trailing binary
  4. Execution
    Env assignment loads attacker code
  5. Impact
    Arbitrary code execution as agent user

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A02:2025 - Security Misconfiguration
ASVS 5.0
V13 - Configuration Configuration hardening
Exploitation Conditions

Requires the target to be running Mistral Vibe with its command permission/allowlist check as the execution gate, and an attacker able to influence a command the agent proposes to execute (e.g. via injected/processed content). The specific enabler is that environment-variable assignments (VAR=value) placed before an allowlisted command are excluded from inspection, so the exploit only works when at least one allowlisted command exists and the shell honors the inline env-var prefix. Limiting factors: the agent must actually reach command execution, and hardened setups that require full-command-line approval, disable auto-run, or scrub environment variables neutralize it. The input's AV:N/PR:N/UI:N should be verified, since real-world triggering depends on how attacker input reaches the agent.

Impact

The input CVSS 4.0 vector is a maximal 10.0 (AV:N/AC:L/AT:N/PR:N/UI:N with full VC/VI/VA and subsequent-system impact), which reads as trivially exploitable and total compromise. That score is likely overstated for an agentic-tool config bypass: real exploitation depends on an attacker being able to influence what command the agent proposes to run (for example via prompt injection in processed content, a malicious repository, or tool output), and on the agent actually reaching the point of executing an allowlisted command. There is no EPSS score, no KEV listing, and no explicit POC in the provided data, so widespread automated exploitation is not evidenced. The signal is a single credible vendor/research advisory (HiddenLayer). Net: a genuinely serious bypass for anyone running Mistral Vibe with command allowlisting as their safety boundary, but the 10.0 rating overstates conditions - treat as high priority for affected users rather than an internet-wide worm risk, and note the AV:N/PR:N/UI:N claim should be verified against how attacker input reaches the agent.

Exploit ScenarioDerived

An attacker seeds content the agent will process - a malicious file, repo, or web page - that steers Mistral Vibe into proposing a command like 'LD_PRELOAD=/tmp/evil.so ls', which the allowlist approves because only 'ls' is checked. When the agent runs it, the attacker's shared object loads and executes with the agent user's privileges, achieving code execution with no explicit user approval. No public POC is confirmed in the provided data, but the technique is straightforward for anyone able to influence the agent's proposed commands.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 11, 2026

Arbitrary code execution in Mistral Vibe (mistralai:mistral-vibe) lets an attacker defeat the agent's command-approval allowlist by prefixing an allowlisted command with shell environment-variable assignments (e.g. FOO=bar allowedcmd). The permission checker inspects only the command token and skips the leading assignments, so attacker-controlled variables such as LD_PRELOAD or PATH execute arbitrary code without user approval. Reported by HiddenLayer; no public exploit identified at time of analysis and not listed in CISA KEV.

RemediationAI

No vendor-released patch version is identified in the provided data - consult the HiddenLayer advisory (https://www.hiddenlayer.com/sai-security-advisory/2026-09-mistral-vibe5) and Mistral's release notes for a fixed build and upgrade to it once published. As compensating controls, run Mistral Vibe with the smallest possible tool/command surface and disable auto-approval so a human reviews every command including its full prefix; where the tool exposes it, require the entire command line (not just the binary) to match the allowlist and reject any line containing '=' before the command. Sandbox the agent (dedicated low-privilege user, container, or restricted seccomp/AppArmor profile) and scrub/deny dangerous environment variables (LD_PRELOAD, LD_LIBRARY_PATH, PATH overrides, PYTHONPATH, NODE_OPTIONS) from the agent's execution context. Trade-offs: strict full-line allowlisting and env scrubbing may break legitimate workflows that set env vars inline, and sandboxing adds operational overhead, but these directly close the bypass until a patch is applied.

Affected VersionsENISA

mistral-vibe 2.6.0 ≤*

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Technical ContextAI · show details

Mistral Vibe is an AI/agentic coding assistant from Mistral AI that gates shell command execution behind an allowlist and a human-approval prompt. The root cause is that the command-safety parser tokenizes the proposed command line but treats leading VAR=value environment assignments as out of scope for inspection, matching only the trailing binary against the allowlist. Because POSIX shells apply those assignments to the command's environment, an attacker can inject dynamic-linker/interpreter overrides (LD_PRELOAD, LD_LIBRARY_PATH, PATH, PYTHONPATH, NODE_OPTIONS, etc.) or redefine lookup paths so that even a 'safe' allowlisted command runs attacker-supplied code. The assigned CWE-15 (External Control of System or Configuration Setting) captures the env-var-control angle, but the effective weakness is an allowlist/command-parsing bypass closer to CWE-77/CWE-78 command injection. CPE identifies the single affected product as cpe:2.3:a:mistralai:mistral-vibe:*.

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Severity by source

Vendor (HiddenLayer) PRIMARY 10.0 CRITICAL
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
vuln.today AI 9.0 CRITICAL

Bypass yields full code execution beyond the agent's sandbox (S:C, C/I/A:H), but requires influencing the agent's proposed command, so AC:H; no standing privileges or explicit user approval needed (PR:N/UI:N).

3.1 AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Primary rating from Vendor (HiddenLayer).

CVSS VectorVendor: HiddenLayer

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
High
Subsequent system: Integrity
High
Subsequent system: Availability
High

DescriptionCVE.org

An arbitrary code execution vulnerability in Mistral Vibe allows an attacker to bypass command permission checks using environment variable assignments preceding allowlisted commands. These assignments are excluded from inspection, enabling attacker-controlled environment variables to cause arbitrary code execution without user approval.

Executive ViewAI

Why It Matters

Mistral Vibe AI agents contain a critical vulnerability allowing arbitrary code execution through command-approval bypass via environment-variable injection. Attackers can execute unauthorized code within agent contexts without triggering approval controls, creating immediate risk of agent compromise for any organization using Mistral Vibe for automated workflows or external integrations.

Business Impact: Severe
Compensating Controls

Until a vendor patch is available: run Mistral Vibe agents in isolated containers with restrictive security policies and limited filesystem access; disable environment-variable expansion in agent command execution if configurable; implement network-level outbound restrictions limiting agent connections to pre-approved services only; validate and sanitize all command inputs to reject patterns containing '=' prefixes; monitor container process execution for unexpected child processes or privilege escalation attempts; and maintain detailed audit logs of all agent command invocations for forensic analysis.

Threat Intelligence Overview

EPSS Score
0.3%
Top 74% exploitable
Prevalence
Low
new Mistral AI agentic coding tool, limited production footprint
Social Media
2
Sightings
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Out-of-Cycle
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
Very High
Technical Impact
Total

Priority Score

50
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +50
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

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CVE-2026-109428 HIGH
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Remote code execution in Mistral Vibe before 2.25.5 allows an attacker to run arbitrary shell commands with the privileg

CVE-2026-67623 HIGH
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Remote code execution in Mistral Vibe before 2.23.3 allows any attacker who can deliver a crafted repository to a victim

Vendor StatusVendor

SUSE

Product Status
openSUSE Tumbleweed Fixed

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