Hello McCaden Hjelm
There is not a direct RSS feed exclusively for Azure security advisories.
Microsoft Security Advisories are a way for Microsoft to communicate security information to customers about issues that may not be classified as vulnerabilities and may not require a security bulletin. Each advisory is accompanied by a Microsoft Knowledge Base Article to provide additional information about any changes or updates being delivered with the advisory’s release.
For more general Microsoft security updates and advisories, please consider the Microsoft Technical Security Notifications, which offer updates on security-related software updates and re-released security updates.
https://learn.microsoft.com/en-us/security-updates/securityadvisories/securityadvisories