# Azure OpenAI: Microsoft publishes a CVSS 9.8 missing authentication CVE

> CVE-2026-119990 is a missing authentication flaw in Azure OpenAI that Microsoft scores 9.8 and records as fixed in a September service build.

- **Severity:** Low: Minor, hard to exploit or mostly theoretical. Good to know.
- **Category:** Vulnerability
- **Published by:** Microsoft
- **Disclosed:** 2026-11-10
- **CVE:** CVE-2026-119990
- **CVSS:** 9.8
- **Affects:** Azure OpenAI
- **Research by:** Microsoft Security Response Center
- **Primary source:** https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-119990
- **Page:** https://theinjection.dev/items/azure-openai-missing-authentication-cve/

Microsoft published CVE-2026-119990 on 10 November 2026, a missing authentication flaw in Azure OpenAI that it scores 9.8 and describes as letting an unauthorized attacker elevate privileges over a network.

## What happened

Microsoft disclosed CVE-2026-119990 on 10 November 2026, naming Azure OpenAI, its hosted service for OpenAI models. Microsoft is the assigning authority, publishes no technical write-up beyond the record, and credits no outside researcher. CISA's enrichment of the record lists exploitation as none, automatable as yes, and the technical impact as total.

## How it works

The weakness is classed as CWE-306, missing authentication for a critical function, and the stated effect is that an unauthorized attacker can elevate privileges over a network. The published vector, AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, describes a remote caller who needs no privileges and no user interaction, with high impact on confidentiality, integrity and availability. Which function lacked the check is not described anywhere in the record.

## Who is affected

Azure OpenAI is the only product named. The record lists the affected range as service builds from 1.0.0 up to, but not including, hyena-infra-build-official/20260923.14, and tags the product as an exclusively hosted service, so no customer-installable patch exists.

## What to do

No patching work follows for customers, because the fix sits in a Microsoft-operated service build and the record's remediation level reads official fix. Teams that keep a register of AI service CVEs should file this one as an inventory note, and ask Microsoft through support if they need the exposure window for an audit.

## Quick facts

- **Affected:** Azure OpenAI, the hosted service: builds from 1.0.0 up to hyena-infra-build-official/20260923.14
- **CVE:** CVE-2026-119990, published 10 November 2026, Microsoft as the assigning authority
- **CVSS:** 9.8 base (v3.1), with exploit maturity unproven and remediation level official fix
- **Attack type:** Missing authentication for a critical function, CWE-306, leading to elevation of privilege
- **Status:** Hosted service with no customer action listed; CISA enrichment lists exploitation as none

## Sources

1. [Microsoft Advisory](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-119990)
2. [GitHub Advisory](https://github.com/advisories/GHSA-298x-8vc9-pjwx)
3. [CVE Record](https://cveawg.mitre.org/api/cve/CVE-2026-119990)