CVE-2023-38180: Microsoft .NET Core and Visual Studio Denial-of-Service Vulnerability

CVE-2023-38180 is a denial-of-service vulnerability affecting Microsoft .NET Core and Visual Studio. An attacker who can trigger the flaw may cause the affected software or applications built on it to become unavailable, disrupting services that depend on those runtimes or development tools. For IT and security teams, this matters because .NET Core underpins many production web services, APIs, and background workers; an unmitigated DoS condition can interrupt operations even when no data is stolen.

Public detail on the exact trigger is limited. Confirm all version ranges, attack preconditions, and fixes against the official Microsoft advisory before acting.

How it works

The vulnerability is described only as an unspecified flaw that permits denial-of-service. In the general class of DoS issues that appear in managed runtimes and IDEs, an attacker typically supplies crafted input or a sequence of requests that exhausts CPU, memory, thread pools, or other finite resources, or that forces an unhandled exception path leading to process termination. Because the CWE is not specified and the vendor has not published exploit mechanics in the material available here, defenders should treat any network-reachable .NET Core endpoint or Visual Studio component that processes untrusted data as potentially in scope. No public proof-of-concept or ransomware linkage is documented for this CVE; assume remote or local triggerability only after reviewing the vendor advisory.

Am I affected? How to find it in your systems

Microsoft .NET Core commonly runs on Windows and Linux servers that host ASP.NET applications, microservices, and containerized workloads; Visual Studio is typically installed on developer workstations and build agents. Inventory steps:

• Enumerate installed .NET runtimes and SDKs with the official dotnet --list-runtimes and dotnet --list-sdks commands, or by querying package managers and Windows Add/Remove Programs.
• Locate Visual Studio installations via the Visual Studio Installer or by searching for devenv.exe and related components on developer machines and CI servers.
• Cross-check every discovered version against the fixed versions listed in the Microsoft security update guide for CVE-2023-38180; do not rely on third-party version matrices.
• Review application logs, IIS/HTTP.sys logs, and container orchestration metrics for sudden spikes in request latency, process crashes, or out-of-memory events that coincide with unusual traffic patterns. Such telemetry is not definitive proof of exploitation but can surface candidates for deeper investigation.

If the software is present and the version is listed as vulnerable, treat the system as affected until the vendor patch is confirmed applied.

How to remediate

Apply the security update released by Microsoft for .NET Core and Visual Studio as soon as operational testing allows. The CISA-required action is to follow the vendor’s mitigation instructions or to discontinue use of the product if no mitigations are available. After patching:

• Restart affected services and verify that the new runtime or Visual Studio build is loaded.
• Re-scan inventories to confirm no residual vulnerable installations remain on servers, containers, or developer images.
• For applications that embed the .NET runtime, rebuild and redeploy so that the patched framework is used at runtime.

Hardening steps that reduce the attack surface for this class of DoS issues include enabling request-size and rate limits at the reverse-proxy or application-gateway layer, configuring process-level resource caps (CPU and memory limits in containers or Windows Job Objects), and ensuring unhandled exceptions are caught and logged rather than allowed to terminate the process.

If you can't patch immediately

Until the vendor update can be deployed, reduce exposure with compensating controls:

• Segment systems that host .NET Core services so that only trusted clients can reach them; place developer workstations running Visual Studio on isolated management networks.
• Apply virtual patching or WAF rules that reject oversized or malformed payloads known to stress .NET parsers, after validating those rules against your own traffic baselines.
• Disable or restrict any optional features or endpoints that process untrusted input if they are not required for business function.
• Increase monitoring of process health, memory consumption, and HTTP error rates so that a DoS attempt is detected and traffic can be blocked quickly.

These measures lower risk but do not eliminate it; schedule the official patch as the primary remediation.

If your data may have been exposed

Denial-of-service vulnerabilities primarily affect availability rather than confidentiality, and no ransomware use is documented for CVE-2023-38180. Nevertheless, any actively exploited vulnerability can be a precursor to broader compromise. If you suspect your environment was targeted, review logs for signs of follow-on activity and consider running a free exposure scan of organizational email addresses against known breach data sets to determine whether credentials or other information have already appeared in public dumps.