CVE-2026-62899 .NET Security Feature Bypass Vulnerability
Medium 5.9
Published
Updated
Check this codebase for CVE-2026-62899 and fix it if it is affected.
What it is: CVE-2026-62899 is a medium-severity vulnerability in Microsoft .Net, published on 11 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-62899 in the wild and no public exploit code.
Affected packages and fixed versions:
- Microsoft.NETCore.App.Runtime.linux-arm (NuGet): affected from 10.0.0; fixed in 10.0.11
- Microsoft.NETCore.App.Runtime.linux-arm (NuGet): affected from 10.0.0; fixed in 10.0.11
- Microsoft.NETCore.App.Runtime.linux-arm (NuGet): affected from 8.0.0; fixed in 8.0.30
- Microsoft.NETCore.App.Runtime.linux-arm (NuGet): affected from 8.0.0; fixed in 8.0.30
- Microsoft.NETCore.App.Runtime.linux-arm (NuGet): affected from 9.0.0; fixed in 9.0.19
- Microsoft.NETCore.App.Runtime.linux-arm (NuGet): affected from 9.0.0; fixed in 9.0.19
- dotnet (Bitnami): affected from 8.0.0; fixed in 8.0.30, 9.0.19, 10.0.11
- dotnet-sdk (Bitnami): affected from 8.0.0; fixed in 8.0.30, 9.0.19, 10.0.11
- Microsoft.NETCore.App.Runtime.linux-arm64 (NuGet): affected from 10.0.0; fixed in 10.0.11
- Microsoft.NETCore.App.Runtime.linux-arm64 (NuGet): affected from 10.0.0; fixed in 10.0.11
- Microsoft.NETCore.App.Runtime.linux-arm64 (NuGet): affected from 8.0.0; fixed in 8.0.30
- Microsoft.NETCore.App.Runtime.linux-arm64 (NuGet): affected from 8.0.0; fixed in 8.0.30
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-62899/ (Markdown: https://insights.sbomify.com/CVE-2026-62899/index.md)
An attacker can bypass security features via HTTP request smuggling in the .NET runtime, requiring a patch to mitigate.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-62899?
CVE-2026-62899 is a medium-severity vulnerability in Microsoft .Net, published on 11 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Inconsistent interpretation of http requests ('http request/response smuggling') in .NET allows an unauthorized attacker to bypass a security feature over a network.
Weakness: CWE-444
Which versions are affected by CVE-2026-62899?
40 open source packages ship an affected version, including Microsoft.NETCore.App.Runtime.linux-arm, dotnet and dotnet-sdk. It affects 3 products.
| Package | Affected | Fixed in |
|---|---|---|
Microsoft.NETCore.App.Runtime.linux-arm NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-arm NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-arm NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-arm NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-arm NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-arm NuGet | From 9.0.0 | 9.0.19 |
34 more packages
dotnet Bitnami | From 8.0.0 | 8.0.30, 9.0.19, 10.0.11 |
dotnet-sdk Bitnami | From 8.0.0 | 8.0.30, 9.0.19, 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-arm64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-arm64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-arm64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-arm64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-arm64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-arm64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-musl-arm NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-musl-arm NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-musl-arm NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-musl-arm NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-musl-arm NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-musl-arm NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-musl-arm64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-musl-arm64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-musl-arm64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-musl-arm64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-musl-arm64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-musl-arm64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-musl-x64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-musl-x64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-musl-x64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-musl-x64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-musl-x64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-musl-x64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-x64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-x64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.linux-x64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-x64 NuGet | From 8.0.0 | 8.0.30 |
Microsoft.NETCore.App.Runtime.linux-x64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.linux-x64 NuGet | From 9.0.0 | 9.0.19 |
Microsoft.NETCore.App.Runtime.osx-arm64 NuGet | From 10.0.0 | 10.0.11 |
Microsoft.NETCore.App.Runtime.osx-arm64 NuGet | From 10.0.0 | 10.0.11 |
Products include Microsoft .Net, Microsoft Visual Studio 2022, Microsoft Visual Studio 2026.
How do I fix CVE-2026-62899?
Upgrade Microsoft.NETCore.App.Runtime.linux-arm to a fixed version for your release line: 10.0.11, 8.0.30 or 9.0.19.
Is CVE-2026-62899 being exploited?
There is no known exploitation of CVE-2026-62899 in the wild and no public exploit code.
Other vulnerabilities in Microsoft .Net
- CVE-2024-43498 .NET and Visual Studio Remote Code Execution Vulnerability
- CVE-2024-0057 NET, .NET Framework, and Visual Studio Security Feature Bypass Vulnerability
- CVE-2026-96957 .NET Security Feature Bypass Vulnerability
- CVE-2026-69439 .NET and Visual Studio Elevation of Privilege Vulnerability
- CVE-2026-71328 .NET and Visual Studio Remote Code Execution Vulnerability
Sources
Also known as BELL-CVE-2026-62899, BIT-dotnet-2026-62899, BIT-dotnet-sdk-2026-62899, GHSA-r6mh-95jw-g7qg, MINI-92hv-2387-w26c, MINI-mh85-jhcm-f9r8 and 1 more.