CVE-2026-66316

Microsoft Edge (Chromium-based) Spoofing Vulnerability

Published Aug 3, 2026 CVSS 3.1 · 5.4 Medium EPSS < 1% KEV · Not listed
Description
Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform spoofing over a network.

Analysis

AI-generated

Technical impact

This vulnerability originates from an origin validation error that allows an unauthorized attacker to spoof source identities over a network. The flaw is categorized as CWE‑346, a weakness that undermines authenticity by permitting an attacker to forge an origin header, potentially leading to deceptive communications or impersonation of legitimate services.

Affected Systems

Microsoft Edge (Chromium‑based) is affected. No specific version information is provided, so all current releases of this browser could be impacted until a fix is released.

Risk and Exploitability

The CVSS score of 5.4 indicates moderate risk, and the EPSS score is not available, making it unclear how frequently the vulnerability is actively exploited. The vulnerability is not listed in the CISA KEV catalog. Likely exploitation would require an attacker to send crafted network traffic that bypasses the browser’s origin validation, enabling spoofed content or connections to appear as legitimate sources.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the latest Microsoft Edge update that contains the fix for this origin validation error.
  • Configure browsers and network devices to enforce strict origin verification and reject packets with mismatched origin headers.
  • Implement network monitoring to detect anomalous origin addresses and use intrusion detection systems to alert on possible spoofing attempts.

Generated by OpenCVE AI on August 4, 2026 at 09:31 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Microsoft microsoft Edge (chromium-based)
Vendors & Products Microsoft microsoft Edge (chromium-based)
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Description Origin validation error in Microsoft Edge (Chromium-based) allows an unauthorized attacker to perform spoofing over a network.
Title Microsoft Edge (Chromium-based) Spoofing Vulnerability
First Time appeared Microsoft
Microsoft edge Chromium
Weaknesses CWE-346
CPEs cpe:2.3:a:microsoft:edge_chromium:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft edge Chromium
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
microsoft
Published
Updated
Nov 10, 2026, 10:36 PM
Reserved
Jul 24, 2026, 6:06 PM
Status
Analyzed
Published
Aug 4, 2026, 12:17 AM
Modified
Oct 23, 2026, 11:10 PM