CVE-2026-21537
CVE-2026-21537 is a high-severity vulnerability in Microsoft Defender For Endpoint with a CVSS 3.x base score of 8.8. 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-94.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- EPSS exploit prediction: 1% (41st percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-7336
- Weakness: CWE-94
- Affected product: Microsoft Defender For Endpoint
- Published:
- Last modified:
Description
Improper control of generation of code ('code injection') in Microsoft Defender for Linux allows an unauthorized attacker to execute code over an adjacent network.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-21537?
- CVE-2026-21537 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-21537 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-21537?
- CVE-2026-21537 affects Microsoft Defender For Endpoint. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-21537?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-21537 have an EU (EUVD) identifier?
- Yes. CVE-2026-21537 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7336.
- When was CVE-2026-21537 published?
- CVE-2026-21537 was published on 2026-02-10 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:microsoft:defender_for_endpoint:-:*:*:*:*:linux:*:*
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