CVE-2026-77900 Azure App Service Remote Code Execution Vulnerability
An unauthorized attacker can execute code remotely due to missing authentication in Azure App Service for Linux.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-77900?
CVE-2026-77900 is a critical missing authorization vulnerability in Microsoft Azure App Service for Linux, published on 8 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Missing authentication for critical function in Azure App Service allows an unauthorized attacker to execute code over a network.
Weakness: CWE-306
Which versions are affected by CVE-2026-77900?
How do I fix CVE-2026-77900?
No fix has been published for CVE-2026-77900 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-77900 being exploited?
There is no known exploitation of CVE-2026-77900 in the wild and no public exploit code.
Sources
Also known as GHSA-9x98-433f-w7ff.