CVE-2026-58630 is a critical flaw (CVSS 10.0) in Azure App Service for Linux. Improper access control lets an unauthorized attacker elevate privileges over a network. The record lists no versions or fix steps, so read the Microsoft guide to see whether you need to act.
What's affected
- Azure App Service for Linux. The record lists no versions.
- Fix: not described in the record. The MSRC guide states any customer action.
How to check if you're exposed
App Service is a managed cloud service. Open the MSRC guide for this CVE and read whether customers must take steps. Then list your App Service apps and review who has contributor access to them.
Cloud service CVEs are not something a dependency scan can find, but the Gold directory keeps the CVE record and weakness class in one place for your change ticket.
What to do now
- Read the MSRC guide for CVE-2026-58630.
- Follow any customer steps it lists.
- Review role assignments and remove broad access.
- Check activity logs for unexpected configuration changes.
Write down what you checked and when. For a managed service the record is part of how you show later that you read the advisory, decided whether it applied, and acted on the result.
Why it matters
This is CWE-284 (Improper Access Control). The vector reads network reachable, no login, scope changed, with high confidentiality and integrity impact. Scope changed means harm can cross a security boundary.
The CISA KEV flag is false. The MSRC page could not be read as plain text, so the mechanism is not described here.
App Service hosts customer code, so a flaw with a changed scope is notable. Whatever the guide says, a periodic review of who can deploy to and configure your apps is the control that stays useful after this CVE is forgotten.
Quick check
Do I need to patch?
For a managed service Microsoft usually applies fixes. Confirm in the MSRC guide.
Sources
Last reviewed: 19 October 2026.
