VulnerabilityDeferred

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 the active workspace without user approval.

CRITICAL 9.3EPSS 0.43%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 4.0: 9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.43% probability · 36th percentile
CISA KEV: Not listed
Weakness: CWE-22
Source: 6f8de1f0-f67e-45a6-b68f-98777fdb759c

References

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.