Quick answers
- Is CVE-2026-66318 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-66318 being exploited in the wild.
- How severe is CVE-2026-66318?
- High severity, with a CVSS score of 8.1, published 4 August 2026.
- Which products and versions are affected?
- Microsoft Edge <UNKNOWN>.
- Is there a fix for CVE-2026-66318?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-66318 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-66318?
- Check whether you run Microsoft Edge or Microsoft Edge Chromium at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
An origin validation error in Microsoft Edge (Chromium-based) allows an attacker to bypass the same-origin policy, a critical security boundary that prevents untrusted websites from accessing data from other origins. The vulnerability can be exploited over the network without authentication or special privileges. An attacker can craft a malicious website or use other delivery mechanisms to trigger the flaw and disclose sensitive information from the victim's browser context, such as session tokens, CSRF tokens, or other protected data. Microsoft has issued security updates to address this vulnerability.
Affected products
- Microsoft Edge <UNKNOWN>
Timeline
- 2026-08-04: disclosed