CVE-2025-36854 EOL ASP.NET 6.0 Remote Code Execution Vulnerability
A race condition in ASP.NET Core allows remote code execution via use-after-free when closing HTTP/3 streams, affecting end-of-life software.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-36854?
CVE-2025-36854 is a high-severity use after free vulnerability in Microsoft .NET 6.0, published on 8 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability ( CVE-2024-38229 https://www.cve.org/CVERecord ) exists in EOL ASP.NET when closing an HTTP/3 stream while application code is writing to the response body, a race condition may lead to use-after-free, resulting in Remote Code Execution.
Per CWE-416: Use After Free https://cwe.mitre.org/data/definitions/416.html , Use After Free is when a product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
This issue affects EOL ASP.NET 6.0.0 <= 6.0.36 as represented in this CVE, as well as 8.0.0 <= 8.0.8, 9.0.0-preview.1.24081.5 <= 9.0.0.RC.1 as represented in CVE-2024-38229 https://www.cve.org/CVERecord .
Additionally, if you've deployed self-contained applications https://docs.microsoft.com/dotnet/core/deploying/#self-contained-deployments-scd targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.
NOTE: This CVE only represents End Of Life (EOL) software components. The vendor, Microsoft, has indicated there will be no future updates nor support provided upon inquiry.
Weakness: CWE-416
Which versions are affected by CVE-2025-36854?
2 open source packages ship an affected version, including dotnet and dotnet-sdk.
| Package | Affected | Fixed in |
|---|---|---|
dotnet Bitnami | From 6.0.0 | 8.0.1 |
dotnet-sdk Bitnami | From 6.0.0 | 6.0.418 |
How do I fix CVE-2025-36854?
Upgrade dotnet to 8.0.1 or later.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2025-36854 being exploited?
There is no known exploitation of CVE-2025-36854 in the wild and no public exploit code.
Sources
Also known as BIT-dotnet-2025-36854, BIT-dotnet-sdk-2025-36854, GHSA-qwjg-j8g7-hwvh.