What is the CVSS score of CVE-2026-21264?

CVE-2026-21264 has a CVSS 3.1 base score of 9.3 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N. EPSS exploitation probability: 0.0%.

Which versions of Account are affected by CVE-2026-21264?

A critical cross-site scripting vulnerability in Microsoft Account systems could allow attackers to impersonate users and gain unauthorized access to organizational accounts and data.. A patch is available.

How to fix or mitigate CVE-2026-21264?

Within 24 hours: Inventory all Microsoft Account dependencies and notify security team; activate monitoring for anomalous authentication patterns. Within 7 days: Implement WAF rules to block XSS payloads targeting Microsoft Account endpoints; enforce mandatory password reset for high-risk users; enable MFA enforcement across all accounts. Within 30 days: Conduct security awareness training on phishing/spoofing attacks; establish incident response procedures for account compromise; coordinate with Microsoft on patch timeline and deploy immediately upon availability.

Account CVE-2026-21264

CRITICAL

Cross-site Scripting (XSS) (CWE-79)

2026-01-22 secure@microsoft.com

Microsoft XSS Account

9.3

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.3 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

CVE Published

Jan 22, 2026 - 23:15 nvd

CRITICAL 9.3

DescriptionCVE.org

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Account allows an unauthorized attacker to perform spoofing over a network.

AnalysisAI

Microsoft Account has a cross-site scripting vulnerability allowing unauthenticated attackers to execute scripts in the context of Microsoft Account pages.

Technical ContextAI

Microsoft Account has a CWE-79 XSS vulnerability that allows unauthenticated attackers to inject malicious scripts through crafted input that executes in victims' browsers when viewing Microsoft Account pages.