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CISA KEV Alert — Active Real-World Exploitation Confirmed
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog and is being actively exploited right now.
Microsoft Entra ID Deserialization Vulnerability (CVE-2026-69836)
High🔴 KEV ALERTConfirmed
DateAugust 21, 2026
CVECVE-2026-69836
Risk Assessment
Client Exposure:High
Briefing Priority:Immediate
Barrier to Entry:Low
📋Executive Summary
CISA has added CVE-2026-69836, a deserialization of untrusted data vulnerability in Microsoft Entra ID, to the Known Exploited Vulnerabilities catalog with a mandatory remediation deadline of August 24, 2026. Deserialization flaws in an identity platform of this scale mean an unauthenticated attacker can execute arbitrary code over a network without needing a valid credential to start. By the time CISA publishes a KEV entry, active exploitation is already underway and your window to act ahead of an incident is measured in hours, not weeks.
⚠️Why It Matters for MSSPs
Your MSSP almost certainly runs Microsoft Entra ID as the identity backbone for your own operations and for a significant portion of your client tenants, which means this vulnerability sits at the center of your own administrative access and your clients' authentication infrastructure simultaneously. If an attacker exploits this in your environment, they inherit your delegated admin relationships and your access to every client tenant you manage. If it hits a client environment before you have warned them and pushed mitigations, you own the conversation about why you said nothing.
✅Recommended Action
In the next 24 hours, audit every Entra ID tenant you manage, starting with your own, and confirm that Microsoft's published mitigations are applied and verified, not just scheduled. Pull your delegated admin access logs for anomalous authentication events going back at least 14 days and treat any unexplained service principal activity as a potential indicator of prior compromise. Send a direct client notification today, not a newsletter, a direct message to each client's primary contact explaining the vulnerability, the action you are taking on their behalf, and what they need to do on their end.
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