Quick answers
- Is CVE-2026-70309 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-70309 being exploited in the wild.
- How severe is CVE-2026-70309?
- Medium severity, with a CVSS score of 5.4, published 28 August 2026.
- Which products and versions are affected?
- Microsoft Edge <UNKNOWN>.
- Is there a fix for CVE-2026-70309?
- 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-2026-70309 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-70309?
- 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
The vulnerability is an origin validation error in Microsoft Edge (Chromium-based) that allows unauthorized attackers to bypass a security feature via network attack. The issue stems from improper validation of request origins, enabling an attacker to circumvent browser security mechanisms designed to protect against cross-origin attacks. The attack is network-reachable and requires no authentication or elevated privileges. An attacker can exploit this to bypass origin-based security controls, potentially gaining unauthorized access to protected functionality or data. Patches are expected to be available through Microsoft's standard security update process.
Affected products
- Microsoft Edge <UNKNOWN>
Timeline
- 2026-08-28: disclosed