How severe is CVE-2021-34485?

CVE-2021-34485 has a CVSS score of 5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-34485?

CVE-2021-34485 affects the following packages: Microsoft.NETCore.App (NuGet), Microsoft.NETCore.App.Runtime.linux-arm (NuGet), Microsoft.NETCore.App.Runtime.linux-arm64 (NuGet), Microsoft.NETCore.App.Runtime.linux-musl-arm64 (NuGet), Microsoft.NETCore.App.Runtime.linux-musl-x64 (NuGet), Microsoft.NETCore.App.Runtime.linux-x64 (NuGet), Microsoft.NETCore.App.Runtime.osx-x64 (NuGet), Microsoft.NETCore.App.Runtime.rhel.6-x64 (NuGet), and 26 more. Ecosystems affected: NuGet.

How do I fix CVE-2021-34485?

Update Microsoft.NETCore.App to 2.1.29 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-34485 is resolved across your whole dependency graph.

How do I detect CVE-2021-34485 in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Microsoft.NETCore.App. 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 CVE-2021-34485 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 CVE-2021-34485?

O3 pinpoints whether CVE-2021-34485 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 CVE-2021-34485 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-34485 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.

When was CVE-2021-34485 published, and has it been updated?

CVE-2021-34485 was published on August 12, 2021 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

.NET NuGet

CVE-2021-34485

MEDIUM

CVE-2021-34485 is a medium-severity (CVSS 5) vulnerability in Microsoft.NETCore.App. O3 Security confirms whether CVE-2021-34485 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

.NET Core Information Disclosure Vulnerability

Also known asBIT-dotnet-2021-34485BIT-dotnet-sdk-2021-34485GHSA-vgwq-hfqc-58wv

Published

Aug 12, 2021

Updated

Jul 8, 2026

Affected

34 pkgs

Patched

34 / 34

Exploits

None indexed

Blast Radius

34 pkgs affected

.NETMicrosoft.NETCore.App.NETMicrosoft.NETCore.App.Runtime.linux-arm.NETMicrosoft.NETCore.App.Runtime.linux-arm64.NETMicrosoft.NETCore.App.Runtime.linux-musl-arm64.NETMicrosoft.NETCore.App.Runtime.linux-musl-x64.NETMicrosoft.NETCore.App.Runtime.linux-x64.NETMicrosoft.NETCore.App.Runtime.osx-x64.NETMicrosoft.NETCore.App.Runtime.rhel.6-x64+26 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

.NET Core and Visual Studio Information Disclosure Vulnerability

Affected Packages

34 total 34 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`Microsoft.NETCore.App`	≥ 2.1.0&&< 2.1.29	2.1.29
.NETNuGet	`Microsoft.NETCore.App.Runtime.linux-arm`	≥ 3.1.0&&< 3.1.18	3.1.18
.NETNuGet	`Microsoft.NETCore.App.Runtime.linux-arm64`	≥ 3.1.0&&< 3.1.18	3.1.18
.NETNuGet	`Microsoft.NETCore.App.Runtime.linux-musl-arm64`	≥ 3.1.0&&< 3.1.18	3.1.18
.NETNuGet	`Microsoft.NETCore.App.Runtime.linux-musl-x64`	≥ 3.1.0&&< 3.1.18	3.1.18
.NETNuGet	`Microsoft.NETCore.App.Runtime.linux-x64`	≥ 3.1.0&&< 3.1.18	3.1.18

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. 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 to 2.1.29 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-34485 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 CVE-2021-34485 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 CVE-2021-34485. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

.NET Core and Visual Studio Information Disclosure Vulnerability

O3 Security · Impact-Aware SCA

Is CVE-2021-34485 in your dependencies?

O3 detects CVE-2021-34485 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