What is CVE-2026-21537?

CVE-2026-21537 is a high-severity vulnerability in Microsoft Defender For Endpoint Linux, classified under Code Injection. CVSS score: 8.8/10. Published 2026-02-10.

How severe is CVE-2026-21537?

High severity. CVSS v3 base score is 8.8 out of 10.

RCE in Microsoft Defender For Endpoint Linux

CVE-2026-21537

Improper control of generation of code ('code injection') in Microsoft Defender for Linux allows an unauthorized attacker to execute code over an adjacent network.

Vulnerability class: RCE (Remote Code Execution)

EPSS: 0.001 (25.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C.

Affected products

Microsoft Defender For Endpoint Linux — versions 101.0.0

Weakness classification (CWE)

CWE-94 — Code Injection

References

Microsoft Defender for Endpoint Linux Extension Remote Code Execution Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-21537?: CVE-2026-21537 is a high-severity vulnerability in Microsoft Defender For Endpoint Linux, classified under Code Injection. CVSS score: 8.8/10. Published 2026-02-10.
How severe is CVE-2026-21537?: High severity. CVSS v3 base score is 8.8 out of 10.