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CVE-2026-40416 Microsoft CVE debrief

A UI misrepresentation vulnerability in Microsoft Edge (Chromium-based) allows network-based spoofing attacks. The vulnerability, classified as CWE-451 (User Interface Misrepresentation of Critical Information), enables an unauthorized attacker to present misleading interface elements to users over a network. Microsoft has addressed this issue in Edge Chromium version 148.0.3967.55 and later. The CVSS 3.1 score of 4.3 reflects medium severity with network attack vector, low attack complexity, no privileges required, but requiring user interaction. The vulnerability was published on May 12, 2026, with the NVD entry last modified on May 18, 2026.

Vendor
Microsoft
Product
Edge Chromium
CVSS
MEDIUM 4.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-12
Original CVE updated
2026-05-18
Advisory published
2026-05-12
Advisory updated
2026-05-18

Who should care

Organizations and individuals using Microsoft Edge (Chromium-based) versions prior to 148.0.3967.55, particularly those in environments where users may be targeted by phishing or social engineering campaigns leveraging browser UI spoofing.

Technical summary

This vulnerability stems from improper handling of user interface elements in Microsoft Edge's Chromium-based rendering engine, allowing attackers to misrepresent critical security information to users. The attack requires network access and user interaction but no authentication. Successful exploitation could deceive users into trusting malicious content based on falsified UI indicators. The fix in version 148.0.3967.55 corrects the UI rendering logic to properly represent security-critical information.

Defensive priority

medium

Recommended defensive actions

  • Update Microsoft Edge (Chromium-based) to version 148.0.3967.55 or later to remediate this spoofing vulnerability.
  • Verify Edge version via edge://settings/help and apply pending updates if available.
  • Educate users to verify URL authenticity and be cautious of unexpected interface prompts, even when the browser appears legitimate.
  • For managed environments, deploy updates through enterprise patch management tools and validate successful installation across endpoints.

Evidence notes

CVE published 2026-05-12; NVD entry modified 2026-05-18. Vendor advisory confirms fix in Edge Chromium 148.0.3967.55. CVSS vector: AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N. CWE-451 classification from Microsoft.

Official resources

official