Critical Denial of Service Vulnerability in .NET on Ubuntu Systems
Severity: High (Score: 74.0)
Sources: Linuxsecurity, launchpad.net, Ubuntu
Published: · Updated:
Keywords: ubuntu, issue, made, consume, excessive, network, dotnet
Severity indicators: critical, issue, ot
Summary
A critical vulnerability has been identified in .NET affecting multiple versions of Ubuntu, including 26.04 LTS and earlier releases. Discovered by Muhammad Abdul Rehman, the flaw allows specially crafted network traffic to cause excessive resource consumption, potentially leading to a denial of service. The vulnerability arises from improper handling of network requests, resulting in a loop without an exit condition. All users of affected Ubuntu versions are advised to update their systems to mitigate this risk. The issue impacts .NET CLI tools and runtimes across several versions. The recommended updates are available for immediate installation. Ubuntu Pro users benefit from extended security coverage for these packages. The vulnerability underscores the importance of timely system updates to maintain security. Key Points: • .NET vulnerability allows denial of service through crafted network traffic. • Affected Ubuntu versions include 26.04 LTS, 25.10, 24.04 LTS, and 22.04 LTS. • Users are urged to update to the latest package versions to mitigate risks.
Detailed Analysis
**Impact** Ubuntu users running versions 22.04 LTS, 24.04 LTS, 25.10, and 26.04 LTS with .NET installed are affected. The vulnerability allows remote attackers to cause denial of service by forcing .NET to consume excessive system resources, potentially disrupting business operations relying on .NET applications. No data breach or data loss is indicated. The issue impacts sectors and geographies where these Ubuntu versions and .NET runtimes are deployed. **Technical Details** The vulnerability arises from .NET incorrectly handling specially crafted network requests, causing an infinite loop with no exit condition. This leads to resource exhaustion and denial of service. The flaw was discovered by Muhammad Abdul Rehman. No CVE identifier or malware/tool names are provided. The attack vector is remote network traffic targeting .NET services. No specific indicators of compromise (IOCs) or infrastructure details are mentioned. **Recommended Response** Apply the updated .NET package versions released for affected Ubuntu versions as detailed in Ubuntu Security Notice USN-8298-1. Perform standard system updates to ensure all relevant .NET components are patched. Monitor network traffic for unusual patterns targeting .NET services. No additional detection signatures or mitigations are specified in the available information.
Source articles (3)
- USN-8298-1: .NET vulnerability — Ubuntu · 2026-05-25
.NET could be made to consume excessive resources if it received specially crafted network traffic. Muhammad Abdul Rehman discovered that .NET incorrectly handled certain network requests, leading to… - Ubuntu 26.04 LTS Dotnet Critical Denial Service Issue USN-8298 — Linuxsecurity · 2026-05-25
A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 26.04 LTS - Ubuntu 25.10 - Ubuntu 24.04 LTS - Ubuntu 22.04 LTS Summary: .NET could be made to consume excessive resource… - 8.0.27-0ubuntu1~25.10.1 — launchpad.net · 2026-05-25
The ASP.NET Core runtime contains everything needed to run .NET web applications. It includes a high performance Virtual Machine as well as the framework libraries used by .NET applications. . ASP.NET…
Timeline
- 2026-05-25 — Vulnerability discovered: Muhammad Abdul Rehman identified a critical flaw in .NET affecting Ubuntu systems, leading to potential denial of service.
- 2026-05-25 — Security notice published: Ubuntu released USN-8298-1 detailing the .NET vulnerability and recommended updates for affected systems.
Related entities
- DDoS (Attack Type)
- Denial of Service (Attack Type)
- Cwe-400 - Uncontrolled Resource Consumption (Cwe)
- Ubuntu (Company)
- Ubuntu Pro (Platform)