🛡️ CVE-2026-62901 — .net
Description
Microsoft Security Advisory CVE-2026-62901 – .NET Denial of Service Vulnerability
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in System.Net.WebSockets. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
An unchecked input for loop condition in .NET 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/428
CVSS Details
- Version: 3.1
- Severity: High
- Score: 7.5
- Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-606: Unchecked Input for Loop Condition
Affected Platforms
- Platforms: Windows, Linux, macOS
- 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.NETCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-arm64) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-x64) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-x86) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-arm) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-arm64) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-musl-arm) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-musl-arm64) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-musl-x64) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-x64) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.osx-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.osx-arm64) | >= 10.0.0, <= 10.0.10 | 10.0.11
[Microsoft.NETCore.App.Runtime.osx-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.osx-x64) | >= 10.0.0, <= 10.0.10 | 10.0.11
<a name=".NET 9"></a>.NET 9
Package name | Affected version | Patched version
------------ | ---------------- | -------------------------
[Microsoft.NETCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-arm64) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-x64) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-x86) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.linux-arm](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-arm) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.linux-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-arm64) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.linux-musl-arm](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-musl-arm) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.linux-musl-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-musl-arm64) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.linux-musl-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-musl-x64) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.linux-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.linux-x64) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.osx-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.osx-arm64) | >= 9.0.0, <= 9.0.18 | 9.0.19
[Microsoft.NETCore.App.Runtime.osx-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.osx-x64) | >= 9.0.0, <= 9.0.18 | 9.0.19
<a name=".NET 8"></a>.NET 8
Package name | Affected version | Patched version
------------ | ---------------- | -------------------------
[Microsoft.NETCore.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-arm64) | >= 8.0.0, <= 8.0.29 | 8.0.30
[Microsoft.NETCore.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.NETCore.App.Runtime.win-x64) | >= 8.0.
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-2026-62901 is classified as CWE-606: Unchecked Input for Loop Condition. The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.
Affected software
CVE-2026-62901 is recorded against 16 packages.
- .net (from 10.0.0 up to 10.0.11)
- dotnet
- dotnet-sdk
- microsoft.netcore.app.runtime.linux-arm (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.linux-arm64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.linux-musl-arm (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.linux-musl-arm64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.linux-musl-x64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.linux-x64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.osx-arm64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.osx-x64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.win-arm64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.win-x64 (from 8.0.0 up to 8.0.30)
- microsoft.netcore.app.runtime.win-x86 (from 8.0.0 up to 8.0.30)
- visual-studio-2022 (from 17.14.0 up to 17.14.38)
- visual-studio-2026 (from 18.8.0 up to 18.8.3)
Timeline and source
Published on 11 August 2026 and last revised on 14 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.
References
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-2026-62902 (6.5 Medium, 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-2026-62897 (7.0 High, published 11 Aug 2026)
- CVE-2026-70354 (7.8 High, published 11 Aug 2026)
- CVE-2026-62886 (7.8 High, published 11 Aug 2026)
- CVE-2026-62909 (7.8 High, published 11 Aug 2026)
- CVE-2026-62871 (7.8 High, published 11 Aug 2026)
Same weakness in other software
These advisories are the same class of weakness (CWE-606: Unchecked Input for Loop Condition) in other software:
- CVE-2026-71439 (published 6 Aug 2026)
- CVE-2026-68077 (6.5 Medium, published 5 Aug 2026)
- CVE-2026-67554 (6.5 Medium, published 5 Aug 2026)
- CVE-2026-66276 (6.5 Medium, published 5 Aug 2026)
- CVE-2026-20301 (8.6 High, published 5 Aug 2026)
- CVE-2026-55731 (published 24 Jul 2026)
- CVE-2026-33800 (6.5 Medium, published 9 Jul 2026)
- CVE-2026-15172 (5.5 Medium, published 8 Jul 2026)
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 | 10.0.11 |
| dotnet | — | — |
| dotnet-sdk | — | — |
| microsoft.netcore.app.runtime.linux-arm | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.linux-arm64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.linux-musl-arm | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.linux-musl-arm64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.linux-musl-x64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.linux-x64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.osx-arm64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.osx-x64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.win-arm64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.win-x64 | 8.0.0 | 8.0.30 |
| microsoft.netcore.app.runtime.win-x86 | 8.0.0 | 8.0.30 |
| visual-studio-2022 | 17.14.0 | 17.14.38 |
| visual-studio-2026 | 18.8.0 | 18.8.3 |
References
Similar Threats
- High CVE-2023-33127
- High CVE-2023-24895
- High CVE-2023-24936
- High CVE-2023-29331
- Medium CVE-2023-32032
Site Security Check
Is .net part of your stack?
CVE-2026-62901 is rated CVSS 8.0 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.
Scan My Site Free →No credit card required · Results in minutes
ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.
