Microsoft Windows Command Injection Vulnerability

Improper neutralization of special elements used in a command ('command injection') in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.

CheckOps priority index

5.6/10 Patch within 7 days

Severity8.8

Probability1.0

Exploitation3/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 9.8% higher than 95.6% of CVEs

CVSS 3.1 8.8 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:

Exploited for 39 days 25 Sept 2026

CISA due date 16 Oct 2026 for US federal agencies

Exploitation probability EPSS · FIRST

EPSS probability (%)Percentile among all CVEs

Exploitation signals 3 / 5

KEV catalog (CISA)13 Oct 2026
Exploited in EUVD (ENISA)25 Sept 2026
Used by ransomwareno
EPSS above 10 %9.8%
No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

Windows Server 2012 R2 (Server Core installation)Windows 11 Version 24H2Windows Server 2025Windows 11 Version 23H2Windows 11 version 26H1Windows 10 Version 21H2Windows 11 Version 25H2Windows Server 2025 (Server Core installation)Windows 10 Version 22H2Windows Server 2019Windows Server 2016Windows Server 2016 (Server Core installation)Outlook.comMicrosoft Edge (Chromium-based)Windows Server 2019 (Server Core installation)Windows Server 2012 R2Windows Server 2022Windows 11 Version 26H2Windows 10 Version 1607Windows 10 Version 1809Windows

Affected versions

6.3.9600.0 <6.3.9600.23470
10.0.26100.0 <10.0.26100.9711
10.0.26100.0 <10.0.26100.33650
10.0.22631.0 <10.0.22631.7652
10.0.28000.0 <10.0.28000.3231
10.0.19044.0 <10.0.19044.7807
10.0.26200.0 <10.0.26200.9711
10.0.19045.0 <10.0.19045.7807
10.0.17763.0 <10.0.17763.9376
10.0.14393.0 <10.0.14393.9612
1.0.0 <20260925.100
1.0.0.0 <154.0.4258.62

Weaknesses (CWE)

CWE-77

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

25 Sept 2026
Exploitation reported (ENISA)
13 Oct 2026
Published
13 Oct 2026
Added to the KEV catalog
16 Oct 2026
CISA remediation due date

References

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