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Fencer Intel
high 8.8

CVE-2026-109428 json

Mistral Vibe < 2.25.5 Permission Bypass via Bash Line Continuation

published 27d ago modified yesterday also EUVD-2026-99221

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

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.

Patch / fix

  • mistralai mistral-vibe 2.25.5

Is CVE-2026-109428 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
14d ago

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 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
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 4.0 8.7 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • mistralai mistral-vibe

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.