Description
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Account allows an unauthorized attacker to perform spoofing over a network.
Published: 2026-01-22
Score: 9.3 Critical
EPSS: < 1% Very Low
KEV: No
Impact: Cross‑site scripting leading to Microsoft Account spoofing
Action: Patch Immediately
AI Analysis

Impact

The vulnerability is an improper neutralization of input during web page generation, identified as a cross‑site scripting (CWE‑79) flaw in Microsoft Account services. Injected scripts execute in the context of the authenticated user, enabling an attacker to generate a spoofed account page that appears legitimate. The attacker can then use the impersonated interface to trick users into revealing credentials, session tokens, or other sensitive information, effectively facilitating phishing or credential theft.

Affected Systems

Microsoft Account services are affected. The CVE entry does not specify particular build or release numbers; all publicly available Microsoft Account deployments should be treated as potentially vulnerable until an official security update is applied.

Risk and Exploitability

The vulnerability carries a high CVSS score of 9.3, yet an EPSS of less than 1 % indicates a very low but non‑zero exploitation likelihood. It is not listed in the CISA KEV catalog. Based on the description, it is inferred that exploitation requires the delivery of malicious JavaScript to a user’s browser, typically via a malicious webpage or a compromised Microsoft Account session that embeds user input into the portal. Once the script runs, the attacker can manipulate the page to impersonate Microsoft services and harvest sensitive data. The combination of high severity and low exploitation probability suggests that vendors and administrators should prioritize applying the patch, as the potential impact is substantial.

Generated by OpenCVE AI on April 16, 2026 at 17:48 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the Microsoft Account security update for CVE‑2026‑21264, available through the Microsoft Security Update Guide.
  • Apply context‑aware output encoding and enable built‑in XSS filtering to ensure all user input is properly sanitized before rendering in the Microsoft Account portal.
  • Enforce multi‑factor authentication on all Microsoft Account logins and monitor for anomalous sign‑in attempts to mitigate credential theft.

Generated by OpenCVE AI on April 16, 2026 at 17:48 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 03 Feb 2026 13:15:00 +0000

Type Values Removed Values Added
First Time appeared Microsoft account
CPEs cpe:2.3:a:microsoft:account:-:*:*:*:*:*:*:*
Vendors & Products Microsoft account

Fri, 23 Jan 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Thu, 22 Jan 2026 23:00:00 +0000

Type Values Removed Values Added
Description Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Account allows an unauthorized attacker to perform spoofing over a network.
Title Microsoft Account Spoofing Vulnerability
First Time appeared Microsoft
Microsoft micrososft Account
Weaknesses CWE-79
CPEs cpe:2.3:a:microsoft:micrososft_account:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft micrososft Account
References
Metrics cvssV3_1

{'score': 9.3, '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'}


Subscriptions

Microsoft Account Micrososft Account
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-04-01T13:49:27.520Z

Reserved: 2025-12-11T21:02:05.738Z

Link: CVE-2026-21264

cve-icon Vulnrichment

Updated: 2026-01-23T20:02:56.629Z

cve-icon NVD

Status : Analyzed

Published: 2026-01-22T23:15:57.407

Modified: 2026-02-03T12:58:31.007

Link: CVE-2026-21264

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-16T18:00:11Z

Weaknesses