Microsoft has resolved a critical elevation-of-privilege vulnerability in its Entra Provisioning Service, tracked as CVE-2026-57100, that scored a near-maximum 9.9 on the CVSS 3.1 scale.
Disclosed on July 2, 2026, the flaw stemmed from a Server-Side Request Forgery (SSRF) weakness that could have allowed low-privileged attackers to escalate access within cloud-hosted identity infrastructure. Microsoft has already remediated the issue on the server side, so no patching or configuration changes are required from customers.
Given Entra’s role as Microsoft’s cloud-native identity and access management platform (the successor to Azure AD), any vulnerability touching its provisioning pipeline warrants close attention from security teams overseeing hybrid identity environments.
The vulnerability lives in the Entra Provisioning Service, the backend component responsible for synchronizing user and group identities between Entra ID and connected applications or on-premises directories.
Microsoft classified the weakness under CWE-918 (Server-Side Request Forgery), a bug class where an application can be tricked into sending crafted requests to unintended internal or external destinations on behalf of the attacker.
In this case, the SSRF condition allowed an authenticated attacker with only low privileges to manipulate provisioning requests in a way that granted elevated permissions a textbook privilege escalation via backend trust abuse.
The severity rating reflects a genuinely dangerous exploitation profile:
- Attack Vector: Network (AV:N) – exploitable remotely over the internet.
- Attack Complexity: Low (AC:L) – no special conditions or timing required.
- Privileges Required: Low (PR:L) – attacker only needs basic authenticated access, not admin rights.
- User Interaction: None (UI:N) – no victim clicks or approvals needed.
- Scope: Changed (S:C) – the exploit affects resources beyond the vulnerable component itself, a hallmark of SSRF issues.
- Confidentiality, Integrity, Availability: High/High/High – successful exploitation could fully compromise data confidentiality, system integrity, and service availability.
The temporal metrics (E:U/RL:O/RC:C) indicate no known exploitation in the wild; an official fix is already available; and Microsoft has confirmed the report as a relatively clean resolution trajectory.
“SSRF vulnerabilities in identity provisioning systems are particularly concerning because they sit at the trust boundary between an organization’s directory and every connected application. When an attacker can coerce that backend into making requests it shouldn’t, they’re not just breaching one service they’re potentially pivoting into the metadata endpoints, internal APIs, or cloud instance services that the provisioning engine is implicitly trusted to reach. This is the kind of flaw that turns a single misconfigured trust relationship into a tenant-wide compromise.”
Who’s Affected
This vulnerability impacts organizations using Microsoft Entra ID’s provisioning capabilities, including:
- Enterprises syncing identities to SaaS applications via Entra’s automatic provisioning connectors.
- Hybrid environments bridging on-premises Active Directory with Entra ID.
- Organizations relying on cross-tenant or B2B provisioning workflows.
Since Entra Provisioning Service operates largely on Microsoft’s cloud infrastructure, the company was able to deploy the fix server-side without requiring tenant administrators to install updates, adjust policies, or restart services.
Mitigation
Microsoft’s advisory explicitly states that no customer action is required. The fix has been rolled out across the service backend, and the CVE record reflects the resolution classification (RC:C). Organizations should nonetheless:
- Review Entra provisioning logs for anomalous privilege changes around early July 2026.
- Audit service principal and application permissions tied to provisioning connectors.
- Confirm no lingering unauthorized role assignments exist from the vulnerability window.
CVE-2026-57100 adds to a growing pattern of SSRF-driven privilege escalation flaws surfacing in cloud identity platforms throughout 2025–2026, as attackers and researchers increasingly probe the backend trust relationships that power automated provisioning and federation.
While Microsoft’s rapid, server-side resolution limits real-world risk here, the case underscores why identity infrastructure not just endpoints remains a top-tier target for both defenders and threat actors.
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