New Passkey Attacks Can Recover Synced Private Keys or Bypass Phishing-Resistant MFA

Summary: Three separate research efforts last week showed ways to defeat passkey protections without breaking their cryptography: SpecterOps replayed YubiKey signatures Windows stored in cleartext, Unit 42 abused Google Password Manager's synced-passkey system in Chrome on Windows, and Mollema used a Windows Hello for Business key from a compromised session without a fresh PIN or biometric check. SpecterOps presented its Pass-the-Passkey work at Black Hat USA 2026 on August 5, and Microsoft assigned CVE-2026-34348, a Windows Event Logging Service information-disclosure issue with a CVSS score of 6.5, to the Windows logging flaw.
Why it matters: Unit 42's Golden Pass-ta-key variant recovers the 32-byte Security Domain Secret that protects synced passkeys, and Google's current implementation offers no way to rotate or revoke it, so the compromise outlasts a single captured login. Starting September 1, 2026, Entra ID users enabled for SMS or voice will be automatically enabled for passkeys, widening the population that depends on these implementation details.

Read the original at The Hacker News ↗

Topics: Vulnerabilities & Patching
Mentions: CVE-2026-34348
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