🛡️ CVE-2026-42899 — .net
Description
Microsoft Security Advisory CVE-2026-42899 – ASP.NET Core Denial of Service Vulnerability
Executive Summary:
Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 8.0, .NET 9.0, and .NET 10.0. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
Loop with unreachable exit condition ('infinite loop') in ASP.NET Core allows an unauthorized attacker to deny service over a network.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/397
CVSS Details
- Version: 3.1
- Severity:
- Score: 7.5
- Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
- Weakness: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
Affected Platforms
- Platforms: All
- Architectures: All
<a name="affected-packages"></a>Affected Packages
The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below
<a name=".NET 10"></a>.NET 10
Package name | Affected version | Patched version
------------ | ---------------- | -------------------------
[Microsoft.AspNetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x86) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-x64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-x64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.osx-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-arm64) | >= 10.0.0, <= 10.0.7 | 10.0.8
[Microsoft.AspNetCore.App.Runtime.osx-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.osx-x64) | >= 10.0.0, <= 10.0.7 | 10.0.8
<a name=".NET 9"></a>.NET 9
Package name | Affected version | Patched version
------------ | ---------------- | -------------------------
[Microsoft.AspNetCore.App.Runtime.win-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-arm64) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x64) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.win-x86) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-arm64) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-arm64) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-musl-x64) | >= 9.0.0, <= 9.0.15 | 9.0.16
[Microsoft.AspNetCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.AspNetCore.App.Runtime.linux-x64) | >= 9.0.0, <= 9.0.15 | 9.0.16
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How this vulnerability can be exploited
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.
CVSS metrics in full
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector: Network — reachable from anywhere that can route to the service.
- Attack complexity: Low — the attack works reliably, with no preparation.
- Privileges required: None — an unauthenticated stranger can try it.
- User interaction: None — nobody has to be tricked into anything.
- Scope: Unchanged — the damage stays inside the vulnerable component.
- Confidentiality impact: None.
- Integrity impact: None.
- Availability impact: High — total loss, or loss the attacker controls.
Weakness class
CVE-2026-42899 is classified as CWE-835: Infinite Loop. A loop condition can never become false for some inputs, hanging the process.
Affected software
CVE-2026-42899 is recorded against 15 packages.
- .net (from 10.0.0 up to 10.0.8)
- dotnet
- dotnet-sdk
- microsoft.aspnetcore.app.runtime.linux-arm (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.linux-arm64 (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.linux-musl-arm (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.linux-musl-arm64 (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.linux-musl-x64 (from 9.0.0 up to 9.0.16)
- microsoft.aspnetcore.app.runtime.linux-x64 (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.osx-arm64 (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.osx-x64 (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.win-arm (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.win-arm64 (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.win-x64 (from 10.0.0 up to 10.0.8)
- microsoft.aspnetcore.app.runtime.win-x86 (from 10.0.0 up to 10.0.8)
Timeline and source
Published on 12 May 2026 and last revised on 15 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.
References
msrc.microsoft.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
bugzilla.redhat.com
security.access.redhat.com
Other advisories for this package
.net has other advisories on record. If you are patching this one, these are worth checking on the same host:
- CVE-2026-62901 (7.5 High, published 11 Aug 2026)
- CVE-2026-62899 (5.9 Medium, published 11 Aug 2026)
- CVE-2026-62898 (7.5 High, published 11 Aug 2026)
- CVE-2026-70354 (7.8 High, published 11 Aug 2026)
- CVE-2026-62897 (7.0 High, published 11 Aug 2026)
- CVE-2026-62909 (7.8 High, published 11 Aug 2026)
- CVE-2026-62886 (7.8 High, published 11 Aug 2026)
- CVE-2026-62902 (6.5 Medium, published 11 Aug 2026)
Same weakness in other software
These advisories are the same class of weakness (CWE-835: Infinite Loop) in other software:
- CVE-2026-8798 (published 8 Aug 2026)
- CVE-2026-71436 (published 6 Aug 2026)
- CVE-2026-71227 (5.1 Medium, published 5 Aug 2026)
- CVE-2026-10686 (5.8 Medium, published 31 Jul 2026)
- CVE-2026-68499 (6.2 Medium, published 31 Jul 2026)
- CVE-2026-67214 (8.0 High, published 29 Jul 2026)
- CVE-2026-59901 (8.0 High, published 29 Jul 2026)
- CVE-2026-67213 (8.0 High, published 29 Jul 2026)
CVE-2026-42899 on other distributions
Each distribution ships its own build and its own fixed version. Pick the one you run:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| .net | 10.0.0 | 10.0.8 |
| dotnet | — | — |
| dotnet-sdk | — | — |
| microsoft.aspnetcore.app.runtime.linux-arm | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.linux-arm64 | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.linux-musl-arm | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.linux-musl-arm64 | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.linux-musl-x64 | 9.0.0 | 9.0.16 |
| microsoft.aspnetcore.app.runtime.linux-x64 | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.osx-arm64 | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.osx-x64 | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.win-arm | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.win-arm64 | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.win-x64 | 10.0.0 | 10.0.8 |
| microsoft.aspnetcore.app.runtime.win-x86 | 10.0.0 | 10.0.8 |
References
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