CVE-2026-85899

Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability

CVE-2026-85899 is fixed in 4 products on 2 platforms, first by Microsoft Edge Dev 156.0.4285.0, released September 17, 2026. It is not reported as exploited. Patch Radar priority: High.

HighFixed on 2 platforms

CVSS

8.1

Important

Exploitation

None reported

Exploitation Unlikely

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0064

51st percentile

<p>Use after free in Microsoft Edge (Chromium-based) allows an authorized attacker to elevate privileges over a network.</p>

Where it's fixed

Product	Fixed in	Fix	Released
Windows apps
Microsoft Edge	155.0.4283.45	Microsoft Edge 155.0.4283.45	Oct 8, 2026
Microsoft Edge Beta	156.0.4314.8	Microsoft Edge Beta 156.0.4314.8	Oct 6, 2026
Microsoft Edge Dev	156.0.4285.0	Microsoft Edge Dev 156.0.4285.0	Sep 17, 2026
Microsoft Edge WebView2 Runtime	155.0.4283.45	Microsoft Edge WebView2 Runtime 155.0.4283.45	Oct 8, 2026
macOS
Microsoft Edge	155.0.4283.45	Microsoft Edge 155.0.4283.45	Oct 7, 2026

Details

Published
October 26, 2026
Weakness
Use After Free
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85899

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