How severe is CVE-2026-87987?

CVE-2026-87987 has a CVSS 4.0 base score of 10.0, rated critical severity.

Is CVE-2026-87987 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-87987?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-87987 published?

CVE-2026-87987 was published on 2026-09-11.

CVE-2026-87987

CVE-2026-87987 is a critical-severity vulnerability with a CVSS 4.0 base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-15.

Key facts

Severity: Critical (CVSS 4.0 base score 10.0)
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-15
Published: 2026-09-11
Last modified: 2026-09-11

Description

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.

Frequently asked questions

What is CVE-2026-87987?: 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.
How severe is CVE-2026-87987?: CVE-2026-87987 has a CVSS 4.0 base score of 10.0, rated critical severity.
Is CVE-2026-87987 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-87987?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-87987 published?: CVE-2026-87987 was published on 2026-09-11.

References

https://www.hiddenlayer.com/sai-security-advisory/2026-09-mistral-vibe5

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