What is the CVSS score of CVE-2026-26128?

CVE-2026-26128 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Microsoft are affected by CVE-2026-26128?

CVE-2026-26128 is a Windows SMB Server vulnerability that allows authorized users to gain elevated system privileges on affected machines.. A patch is available.

How to fix or mitigate CVE-2026-26128?

Within 24 hours: inventory all Windows systems running SMB Server and identify those with domain users or service accounts; restrict SMB access via firewall rules to only necessary network segments. Within 7 days: implement enhanced monitoring of SMB authentication and privilege escalation attempts; review and audit user access levels across affected systems. Within 30 days: develop a patching timeline with the vendor; evaluate network segmentation strategies to isolate high-value assets; conduct privilege access management (PAM) review to minimize accounts capable of exploiting this vulnerability.

Microsoft CVE-2026-26128

HIGH

Improper Authentication (CWE-287)

2026-03-10 secure@microsoft.com

Microsoft Authentication Bypass

7.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.8 HIGH

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:55 vuln.today

CVE Published

Mar 10, 2026 - 18:18 nvd

HIGH 7.8

DescriptionCVE.org

Improper authentication in Windows SMB Server allows an authorized attacker to elevate privileges locally.

AnalysisAI

Windows SMB Server's authentication mechanism can be bypassed by local authenticated users to gain elevated privileges on affected systems. This high-severity vulnerability (CVSS 7.8) impacts confidentiality, integrity, and availability, though no patch is currently available. Organizations should implement compensating controls and monitor for exploitation attempts targeting this authentication weakness.

Technical ContextAI

Classified as CWE-287 (Improper Authentication). Improper authentication in Windows SMB Server allows an authorized attacker to elevate privileges locally.