What is the CVSS score of CVE-2026-21253?

CVE-2026-21253 has a CVSS 3.1 base score of 7.0 (High). CVSS vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Mailslot File System are affected by CVE-2026-21253?

A privilege escalation vulnerability in the Windows Mailslot File System allows authorized users to gain elevated system access.. A patch is available.

How to fix or mitigate CVE-2026-21253?

Within 24 hours: Identify and inventory all Windows systems using Mailslot functionality and assess exposure; brief security and IT leadership on containment strategy. Within 7 days: Implement enhanced monitoring for unauthorized privilege escalation attempts; restrict Mailslot access through application whitelisting and least-privilege access controls where operationally feasible. Within 30 days: Monitor vendor security advisories for patch availability; conduct risk assessment for business-critical systems and prioritize patching upon availability; consider air-gapping or isolating high-value systems until patched.

Mailslot File System CVE-2026-21253

HIGH

Use After Free (CWE-416)

2026-02-10 secure@microsoft.com

Use After Free Denial Of Service Memory Corruption

7.0

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.0 HIGH

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

Attack Vector

Local

Attack Complexity

High

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:02 vuln.today

CVE Published

Feb 10, 2026 - 18:16 nvd

HIGH 7.0

DescriptionCVE.org

Use after free in Mailslot File System allows an authorized attacker to elevate privileges locally.

AnalysisAI

Use after free in Mailslot File System allows an authorized attacker to elevate privileges locally. [CVSS 7.0 HIGH]

Technical ContextAI

Classified as CWE-416 (Use After Free). Affects Windows 10 1607. Use after free in Mailslot File System allows an authorized attacker to elevate privileges locally.