Microsoft .NET patches six new CVEs
ANSSI advisory details six .NET and ASP.NET Core vulnerabilities enabling RCE, privilege escalation, DoS, and data leaks; patch to fixed versions.
Sourcecert.ssi.gouv.fr — open the original
What to check
- Applies to
- The 6 CVEs named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- No exploitation in the wild and no public exploit is recorded for the CVEs named.
ANSSI (CERT-FR) issued an advisory covering six vulnerabilities in Microsoft .NET affecting .NET Framework 3.5/4.6.2-4.8.1, .NET 8.0/9.0/10.0/11.0 (RC1), and ASP.NET Core across Windows, Linux, and macOS. The flaws collectively allow remote code execution, privilege escalation, remote denial of service, and confidentiality breaches, though the advisory does not specify which CVE maps to which impact individually. No exploitation in the wild is mentioned; this is a routine vendor patch bulletin.
Affected versions span a wide range of .NET releases across all three major operating systems, indicating broad exposure for any organization running .NET-based applications or services. Microsoft published fixes on September 8, 2026, and ANSSI directs administrators to the official Microsoft Security Response Center bulletins for patch details. No proof-of-concept exploit code, IOCs, or threat actor attribution are included in this advisory; it is a standard vulnerability disclosure requiring timely patch management.
Defenders should prioritize applying the vendor-supplied updates to bring installations to the fixed versions listed (e.g., .NET 8.0.130/8.0.424, 9.0.120/9.0.317, 10.0.111/10.0.400, ASP.NET Core 8.0.31/9.0.20/10.0.12, and corresponding .NET Framework updates). Given the range of impacts including RCE and privilege escalation, patching should be treated as a priority for internet-facing or otherwise exposed .NET/ASP.NET Core services.
Mentioned in this report
Source reporting: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-1146
Free public brief. Slack alerts on the vendors you run come with the paid plans, and a new account gets three days of them, no card.
What this brief leaves out
This page is the free tier: the write-up, the severity, the names. In the app the same report carries live profiles of the CVEs it names. The paid plans add the security research and news reporting the free tier leaves out.
It sits in a corpus of 16,436 reports from 149 sources, 661 of them written in the last seven days, and it grows through the day.
A new account starts with three days of all of it, no card, then keeps the government and CERT reporting free. Slack alerts are a paid-plan feature: name the vendors you run and Slack hears about the reports that touch them, not the rest of the week's. Nothing is charged unless you subscribe.
Create a free account What it costs