Microsoft has disclosed a critical missing-authentication flaw in Azure AI Foundry that lets an unauthenticated remote attacker elevate privileges, carrying the maximum possible CVSS base score of 10.0.
What Is It
CVE-2026-85889 is a missing authentication for a critical function (CWE-306) in Microsoft Azure AI Foundry. Per the vendor description, the flaw "allows an unauthorized attacker to elevate privileges over a network." Microsoft ([email protected]) is the assigning source and published the record on 2026-09-17. NVD currently lists the vulnerability status as Received, meaning the record has not yet completed NVD analysis.
The CVSS v3.1 vector is AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H, base score 10.0, CRITICAL, with an exploitability subscore of 3.9 and an impact subscore of 6.0.
Why It Matters
Every exploitability metric is at its worst value: the attack is reachable over the network, requires low complexity, needs no privileges, and requires no user interaction. The scope is Changed, meaning successful exploitation affects resources beyond the vulnerable component's security authority; that scope change is what pushes the score to a full 10.0. Confidentiality, integrity, and availability impacts are all rated High.
Microsoft tags the CVE as exclusively-hosted-service, which places the vulnerable functionality in Microsoft's own cloud rather than in customer-deployed software.
What's Vulnerable
- Vendor: Microsoft
- Product: Azure AI Foundry
- Versions: listed as
-(affected), with no version boundaries provided
No CPE entries are present in the NVD record, consistent with the exclusively-hosted-service designation.
Patch Status
Exploitation status for CVE-2026-85889 is not established by the records reviewed here. The NVD entry is still in Received state and carries no exploitation or remediation-deadline data, and the sources consulted for this brief do not speak to whether the CVE appears in CISA's Known Exploited Vulnerabilities catalog. Because the catalog is updated continuously, defenders should query it directly rather than infer exploitation status, or the absence of it, from this brief.
Because the CVE is tagged as an exclusively hosted service, no customer-installable patch is identified in the source material. Microsoft's MSRC update guide entry is the authoritative reference for current remediation status; the supplied data does not state what fix, if any, has been applied service-side. Organizations using Azure AI Foundry should consult the MSRC entry directly.
Sources
- NVD, CVE-2026-85889: https://nvd.nist.gov/vuln/detail/CVE-2026-85889
- Microsoft MSRC Update Guide; CVE-2026-85889: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85889