CVE-2026-21264CWE-79

Microsoft Account Spoofing Vulnerability

Critical 路 published January 22, 2026

CVSS v3.1
9.3
EPSS
0%
Percentile
34.4
In the wild
Unconfirmed
What it is

馃毃 An attacker can exploit this XSS vulnerability in Microsoft Account to spoof users with mind-blowingly simple tricks! 馃敟 Think of it like an unfiltered restaurant where a sneaky diner can swap the menu items with whatever they want, serving up something entirely different to unsuspecting customers. This vulnerability allows unauthorized attackers to craft misleading experiences that compromise user trust. The consequences could be absolutely devastating; attackers could impersonate legitimate users, steal sensitive information, or redirect users to malicious sites. In a worst-case scenario, this could lead to identity theft or unauthorized access to personal data.

Put simply

Think of it like an unfiltered restaurant where a sneaky diner can swap the menu items with whatever they want, serving up something entirely different to unsuspecting customers. This vulnerability allows unauthorized attackers to craft misleading experiences that compromise user trust. This vulnerability arises from improper handling of user input during web page generation, allowing attackers to inject malicious scripts into the content that gets rendered to other users' browsers.

What to do

The consequences could be absolutely devastating; attackers could impersonate legitimate users, steal sensitive information, or redirect users to malicious sites. In a worst-case scenario, this could lead to identity theft or unauthorized access to personal data. Immediate action is essential: patch to the latest version of Microsoft Account, review your web application firewall settings, and implement strict input validation across your applications to prevent similar exploits. Don鈥檛 delay; secure your users now! You've got this! Take action, and you'll be a security hero in no time. 馃Ω

The record
Technical detail
CVSS v3.1
9.3 路 CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N/E:U/RL:O/RC:C
CVSS v4.0
Not supplied
EPSS
0.00413 路 34.4th percentile
Weakness
CWE-79 路 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-01-22T22:47Z
EPSS history
Timeline
  • 22 JAN 22:47Z
    Microsoft Account Spoofing Vulnerability
    cvelistv5