Improper Authorization in Handler for Custom URL Scheme in Microsoft Authenticator for IOS and Microsoft Authenticator for Android - CVE-2026-26123
Published: March 10, 2026
Vulnerability identifier: #VU123716
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-26123
CWE-ID: CWE-939
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to compromise the target system.
The vulnerability exists due to improper authorization in handler for custom URL scheme in Microsoft Authenticator. A remote attacker can gain access to sensitive information if the user selects a malicious application as the handler for the sign‑in deep link.
Affected software
Microsoft Authenticator for IOS
Microsoft Authenticator for Android
Microsoft Authenticator for Android
How to mitigate CVE-2026-26123
Install updates from vendor's website.
Microsoft Authenticator for IOS - update to 6.8.40
Microsoft Authenticator for Android - update to 6.2511.7533
Microsoft Authenticator for Android - update to 6.2511.7533