Junglewise Threat Intelligence

CVE-2026-66313: Microsoft Edge origin validation error allows local tampering

CVE-2026-66313 · Severity: medium · CVSS 6.8 · Published 2026-08-04

Technologies: Microsoft Edge Chromium, Microsoft Edge. Vendors: Microsoft.

Executive brief

Microsoft Edge, Chromium's integration in Windows browsers, contains an origin validation flaw that allows an attacker on the same system to tamper with browser data or operations locally. This could compromise user sessions, stored credentials, or allow injection of malicious content without network-level detection.

Technical details

The vulnerability is an origin validation error in Microsoft Edge (Chromium-based). It permits local tampering by an unauthorized attacker, likely exploitable via local file system access or inter-process communication without strong origin checks. Exploitation requires local access (same machine) and does not require network connectivity. An attacker can manipulate browser state, cached data, or session information. Patches are likely available through Microsoft Security Updates; consult MSRC guidance for remediation.

Affected products

  • Microsoft Edge <UNKNOWN>

Timeline

  • 2026-08-04: disclosed

References

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