
CVE-2026-80097: How a Zero-Permission Android App Could Steal Your Corporate Microsoft Tokens
In October 2026, security researcher Ofek Levin of Enclave disclosed CVE-2026-80097, an 8.6 CVSS-rated flaw in Microsoft Authenticator for Android that allowed any unprivileged app to impersonate trusted Microsoft applications such as Teams and harvest OAuth tokens for a victim's work account. The vulnerability resided in the publicly accessible AccountChooserActivity component, which accepted attacker-supplied identity claims and performed a flawed signature check that could be bypassed because the legitimate target app was genuinely installed on the device. Tokens returned in testing granted read/write access to corporate email, files, and calendars. Microsoft patched the flaw in Authenticator version 6.2606.4246 as part of September 2026 Patch Tuesday. This incident illustrates the continued risk of over-privileged mobile authentication brokers and weak inter-app trust validation. As enterprises expand mobile-first workforce strategies, OAuth token theft via mobile app impersonation is emerging as a high-value, low-noise vector that bypasses traditional perimeter defenses and directly compromises identity infrastructure.
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