How severe is GHSA-rh58-r7jh-xhx3?

GHSA-rh58-r7jh-xhx3 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-rh58-r7jh-xhx3?

GHSA-rh58-r7jh-xhx3 affects the following packages: Microsoft.NETCore.App.Runtime.win-x86 (NuGet), Microsoft.NETCore.App.Runtime.win-x86 (NuGet), Microsoft.NETCore.App.Runtime.win-x64 (NuGet), Microsoft.NETCore.App.Runtime.win-x64 (NuGet), Microsoft.NETCore.App.Runtime.win-arm64 (NuGet), Microsoft.NETCore.App.Runtime.win-arm64 (NuGet), Microsoft.NETCore.App.Runtime.win-arm (NuGet), Microsoft.NETCore.App.Runtime.win-arm (NuGet), and 25 more. Ecosystems affected: NuGet.

How do I fix GHSA-rh58-r7jh-xhx3?

Update Microsoft.NETCore.App.Runtime.win-x86 to 3.1.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rh58-r7jh-xhx3 is resolved across your whole dependency graph.

How do I detect GHSA-rh58-r7jh-xhx3 in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.NETCore.App.Runtime.win-x86. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-rh58-r7jh-xhx3 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-rh58-r7jh-xhx3?

O3 pinpoints whether GHSA-rh58-r7jh-xhx3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-rh58-r7jh-xhx3 actively exploited in the wild?

No public exploit code has been indexed for GHSA-rh58-r7jh-xhx3 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-rh58-r7jh-xhx3?

GHSA-rh58-r7jh-xhx3 has an EPSS (Exploit Prediction Scoring System) score of 3.7%, placing it in the 88th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was GHSA-rh58-r7jh-xhx3 published, and has it been updated?

GHSA-rh58-r7jh-xhx3 was published on October 25, 2022 and was last updated on December 1, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

GHSA-rh58-r7jh-xhx3: .NET Core Elevation of Privilege Vulnerabi…

EPSS Exploitation Probability

via FIRST.org ↗

3.7%probability of exploitation in next 30 days

Lower Risk88th percentile+0.37%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

33 pkgs affected

.NETMicrosoft.NETCore.App.Runtime.win-x86.NETMicrosoft.NETCore.App.Runtime.win-x86.NETMicrosoft.NETCore.App.Runtime.win-x64.NETMicrosoft.NETCore.App.Runtime.win-x64.NETMicrosoft.NETCore.App.Runtime.win-arm64.NETMicrosoft.NETCore.App.Runtime.win-arm64.NETMicrosoft.NETCore.App.Runtime.win-arm.NETMicrosoft.NETCore.App.Runtime.win-arm+25 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 5.0 and .NET Core 3.1. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

A denial of service vulnerability exists in .NET 5.0, .NET Core 3.1 and .NET Core 2.1 where .NET (Core) server applications providing WebSocket endpoints could be tricked into endlessly looping while trying to read a single WebSocket frame.

Patches

If you're using .NET 5.0, you should download and install Runtime 5.0.9 or SDK 5.0.206 (for Visual Studio 2019 v16.8) or SDK 5.0.303 (for Visual Studio 2019 V16.10) from https://dotnet.microsoft.com/download/dotnet-core/5.0.
If you're using .NET Core 3.1, you should download and install Runtime 3.1.18 or SDK 3.1.118 (for Visual Studio 2019 v16.4) or 3.1.412 (for Visual Studio 2019 v16.7 or later) from https://dotnet.microsoft.com/download/dotnet-core/3.1.
If you're using .NET Core 2.1, you should download and install Runtime 2.1.29 or SDK 2.1.525 (for Visual Studio 2019 v15.9) or 2.1.817 from https://dotnet.microsoft.com/download/dotnet-core/2.1.

Other Details

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/194
An Issue for this can be found at https://github.com/dotnet/runtime/issues/57175
MSRC details for this can be found at https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2021-26423

Affected Packages

33 total 33 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`Microsoft.NETCore.App.Runtime.win-x86`	≥ 3.1.0&&< 3.1.18	3.1.18
.NETNuGet	`Microsoft.NETCore.App.Runtime.win-x86`	≥ 5.0.0&&< 5.0.9	5.0.9
.NETNuGet	`Microsoft.NETCore.App.Runtime.win-x64`	≥ 3.1.0&&< 3.1.18	3.1.18
.NETNuGet	`Microsoft.NETCore.App.Runtime.win-x64`	≥ 5.0.0&&< 5.0.9	5.0.9
.NETNuGet	`Microsoft.NETCore.App.Runtime.win-arm64`	≥ 3.1.0&&< 3.1.18	3.1.18
.NETNuGet	`Microsoft.NETCore.App.Runtime.win-arm64`	≥ 5.0.0&&< 5.0.9	5.0.9

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.NETCore.App.Runtime.win-x86. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Microsoft.NETCore.App.Runtime.win-x86 to 3.1.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-rh58-r7jh-xhx3 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-rh58-r7jh-xhx3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-rh58-r7jh-xhx3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 5.0 and .NET Core 3.1. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. A denial of service vulnerability exists in .NET 5.0, .NET Core 3.1 and .NET Core 2.1 where .NET (Core) server applications providing WebSocket endpoints could be tricked into endlessly looping while trying to read a single WebSocket frame. ### Patches * If you're using .NET 5.0, you should download and install Runtime 5.0.9 or SDK 5.0.206 (for Visua

O3 Security · Impact-Aware SCA

Is GHSA-rh58-r7jh-xhx3 in your dependencies?

O3 detects GHSA-rh58-r7jh-xhx3 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

GHSA-rh58-r7jh-xhx3