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CVE-2026-57108 is a type confusion vulnerability in Microsoft .NET Core that allows an unauthenticated remote attacker to trigger a denial-of-service condition over a network. The flaw resides in how the .NET runtime handles resource type allocation and access. Specifically, the runtime allocates or initializes a resource (such as a pointer, object, or variable) using one type, but later accesses that resource using a type that is incompatible with the original type – a weakness classified under CWE-843 (Access of Resource Using Incompatible Type).
An attacker can exploit this by sending specially crafted data over the network to a vulnerable .NET Core application that processes untrusted input. When the runtime attempts to interpret the crafted data as an incompatible type, the type confusion triggers an exception that can crash or freeze the affected application. Because the attack requires no authentication and can be performed remotely with low complexity, the vulnerability is highly accessible to malicious actors.
The affected products include Microsoft .NET 8.0 (versions 8.0.0 up to but not including 8.0.29), .NET 9.0 (versions 9.0.0 up to but not including 9.0.18), and .NET 10.0 (versions 10.0.0 up to but not including 10.0.6). The vulnerability was published on July 14, 2026, and the NVD last modified the record on July 20, 2026. The CVSS v3.1 base score is 7.5 (High), with the vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. This indicates a network‑attackable vector, low attack complexity, no privileges required, no user interaction, and a high impact on availability with no impact on confidentiality or integrity.
The CISA ADP has assessed the vulnerability with SSVC metrics: Exploitation = none, Automatable = yes, Technical Impact = partial. The EPSS probability is approximately 1.1% (62nd percentile) as of July 16, 2026. No known public exploits are currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Microsoft has released security updates to address the flaw, and administrators are strongly advised to apply the latest patches for their respective .NET versions.
DailyCVE Form:
Platform: Microsoft .NET Core
Version: 8.0/9.0/10.0
Vulnerability: Type Confusion (CWE‑843)
Severity: High (7.5 CVSS)
Date: July 14, 2026
Prediction: Patch by July 2026
What Undercode Say:
Analytics & Threat Intelligence
- CVSS Score: 7.5 (High)
- EPSS Probability: 1.1% (62nd percentile)
- Exploit Price Estimate: USD $5,000 – $25,000
- SSVC: Exploitation none, Automatable yes, Technical Impact partial
- CISA KEV: Not listed
- Nessus ID: 327178
Bash Commands & Code Snippets
Check installed .NET versions:
dotnet --list-runtimes dotnet --info
Verify patch level for .NET 8.0 (fixed version ≥ 8.0.29):
dotnet --list-runtimes | grep "Microsoft.NETCore.App 8.0"
For Ubuntu 24.04, upgrade dotnet8 package:
sudo apt update sudo apt install dotnet8=8.0.129-8.0.29-0ubuntu1~24.04.1
Check for available security updates (Red Hat/CentOS):
sudo yum update dotnet-sdk-8.0 sudo yum update dotnet-runtime-8.0
Monitor application logs for type‑confusion related crashes:
journalctl -u your-dotnet-service -f | grep -i "type|confusion|access violation"
Exploit:
An unauthenticated attacker can exploit CVE-2026-57108 remotely over a network by sending maliciously crafted data to a vulnerable .NET Core application. The attack requires no special privileges or user interaction, and the attack complexity is low, making it easily automatable. The crafted payload causes the .NET runtime to misinterpret a resource type, leading to an unhandled exception that crashes or hangs the application process. Since the vulnerability lies in the core runtime, any application that processes untrusted network input – such as web APIs, microservices, or TCP/UDP listeners – is potentially affected. No technical details or proof‑of‑concept exploits are publicly available at this time, but the low barrier to entry and high availability impact make this a prime target for attackers.
Protection:
- Apply the official Microsoft security update for your .NET version: upgrade to .NET 8.0.29, .NET 9.0.18, or .NET 10.0.6 or later.
- If immediate patching is not possible, restrict external network access to the application so that only trusted traffic reaches the vulnerable component.
- Implement application‑level input validation and sanitization for all untrusted data.
- Deploy robust exception handling and graceful degradation mechanisms to prevent full application crashes from type‑confusion errors.
- Enable comprehensive logging and monitoring to detect anomalous crashes or repeated access violations.
- Use a Web Application Firewall (WAF) or network intrusion detection system to filter suspicious payloads.
- Regularly audit and update all .NET runtime dependencies in production environments.
Impact:
Successful exploitation of CVE-2026-57108 results in a total loss of availability for the affected application or service. The attacker can cause the application to crash or become unresponsive, denying service to legitimate users. Because the vulnerability is network‑reachable, requires no authentication, and is automatable, it poses a significant risk to internet‑facing .NET Core applications. The impact is confined to availability – confidentiality and integrity are not affected – but a sustained denial‑of‑service can severely disrupt business operations, lead to financial losses, and damage reputation. With an estimated exploit price of $5,000–$25,000, there is economic incentive for attackers to develop and deploy exploits once technical details emerge. Organizations running affected versions should prioritize patching to mitigate the risk of service interruption.
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Sources:
Reported By: nvd.nist.gov
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