CVE-2026-77900: Azure App Service Remote Code Execution Vulnerability

Overview

Severity
Critical (CVSS 9.8)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Patch Tuesday
2026-Oct
Released
2026-10-08

Description

Missing authentication for critical function in Azure App Service allows an unauthorized attacker to execute code over a network.

FAQ

Why are there no links to an update or instructions with steps that must be taken to protect from this vulnerability? This vulnerability has already been fully mitigated by Microsoft. There is no action for users of this service to take. The purpose of this CVE is to provide further transparency. Please see Toward greater transparency: Unveiling Cloud Service CVEs for more information.

Affected Products (1)

Azure

  • Azure App Service for Linux

Acknowledgments

<a href="https://www.linkedin.com/in/vamsi-nukavarapu/">Vamsi Nukavarapu</a> with <a href="https://www.microsoft.com/">Microsoft</a>

Revision History

  • 2026-10-08: Information published.