CVE-2021-34532: ASP.NET Core and Visual Studio Information Disclosure Vulnerability

Severity: low (CVSS 2.1 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-08-12 · updated 2026-08-10

Description

ASP.NET Core and Visual Studio Information Disclosure Vulnerability

Affected products

Microsoft .NET Core: from 2.1 through 2.1.2; from 3.1 through 3.1.17; from 5.0 through 5.0.8
Microsoft Visual Studio 2019: from 16.0 through 16.10; 8.10
Microsoft ASP.NET Core 2.1: from 2.0 before 2.1.29 — fixed in 2.1.29
Microsoft ASP.NET Core 3.1: from 3.0 before 3.1.18 — fixed in 3.1.18
Microsoft ASP.NET Core 5.0: from 5.0 before 5.0.9 — fixed in 5.0.9
Microsoft Visual Studio 2019 version 16.10 (includes 16.0 - 16.9): from 16.10.0 before 16.10.5 — fixed in 16.10.5
Microsoft Visual Studio 2019 version 16.4 (includes 16.0 - 16.3): from 16.0 before 16.4.25 — fixed in 16.4.25
Microsoft Visual Studio 2019 version 16.7 (includes 16.0 – 16.6): from 16.0.0 before 16.7.18 — fixed in 16.7.18
Microsoft Visual Studio 2019 version 16.9 (includes 16.0 - 16.8): from 15.0.0 before 16.9.10 — fixed in 16.9.10
Microsoft Visual Studio 2019 for Mac version 8.10: from 8.1.0 before 8.10.7 — fixed in 8.10.7

How to fix

Upgrade to a fixed version: Microsoft ASP.NET Core 2.1 2.1.29; Microsoft ASP.NET Core 3.1 3.1.18; Microsoft ASP.NET Core 5.0 5.0.9; Microsoft Visual Studio 2019 version 16.10 (includes 16.0 - 16.9) 16.10.5; Microsoft Visual Studio 2019 version 16.4 (includes 16.0 - 16.3) 16.4.25; Microsoft Visual Studio 2019 version 16.7 (includes 16.0 – 16.6) 16.7.18; Microsoft Visual Studio 2019 version 16.9 (includes 16.0 - 16.8) 16.9.10; Microsoft Visual Studio 2019 for Mac version 8.10 8.10.7. Check the vendor advisory for mitigations.

References

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