CVE-2026-33843
Published: 22 May 2026
Summary
CVE-2026-33843 is a critical-severity Authentication Bypass Using an Alternate Path or Channel (CWE-288) vulnerability in Microsoft Entra Id. Its CVSS base score is 9.1 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 37.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-31519
Vulnerability details
Authentication bypass using an alternate path or channel in Microsoft Azure Active Directory B2C allows an unauthorized attacker to elevate privileges over a network.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Auth bypass vuln in public-facing Azure AD B2C service directly enables network-based initial access via exploitation of the exposed identity service (T1190) or external remote auth services (T1133).
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Authorizing remote access reduces the ability to bypass authentication via unauthorized alternate remote channels.
Users can identify logons via alternate paths or channels by reviewing the previous logon time.
Adaptive requirements can apply across access paths, reducing the ability to bypass authentication via alternate channels or paths.
Centralized IdPs close alternate authentication paths that enable bypass.
Enforces authentication for non-organizational users, making it harder to bypass via alternate paths or channels.
Requires authentication to occur exclusively over the isolated trusted path, directly preventing bypass via alternate or untrusted channels.