CVE-2021-34485: .NET Core and Visual Studio Information Disclosure Vulnerability

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MEDIUM 5.0WATCHLISTUPGRADEUPGRADEUPGRADE

CVE-2021-34485 is a medium-severity flaw (CVSS 5.0) affecting .net, .net core, powershell core. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

.NET Core and Visual Studio Information Disclosure Vulnerability

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Weakness	CWE-200
Published	2021-08-12
Last modified	2026-10-07

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-10-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-08-12 18:15 UTCPublished CVE record published
2026-10-07 17:16 UTCUpdated Record last modified

microsoft .net UPGRADE

Affected: >= 5.0 and <= 5.0.8

Fixed in: newer than 5.0.8

Safe to downgrade to: a release before 5.0

1. Check installed version

apt-cache policy .net || rpm -q .net || .net --version

2. UPGRADE to newer than 5.0.8 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade .net

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade .net

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 5.0 (Debian / Ubuntu)

apt-cache madison .net sudo apt install .net=<VERSION_BEFORE_5.0> sudo apt-mark hold .net

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list .net sudo dnf downgrade .net-<VERSION_BEFORE_5.0> sudo dnf versionlock add .net

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

microsoft .net core UPGRADE

Affected: >= 2.1 and <= 2.1.28 · >= 3.1 and <= 3.1.17

Fixed in: newer than 3.1.17

Safe to downgrade to: a release before 2.1

1. Check installed version

apt-cache policy .net-core || rpm -q .net-core || .net-core --version

2. UPGRADE to newer than 3.1.17 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade .net-core

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade .net-core

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.1 (Debian / Ubuntu)

apt-cache madison .net-core sudo apt install .net-core=<VERSION_BEFORE_2.1> sudo apt-mark hold .net-core

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list .net-core sudo dnf downgrade .net-core-<VERSION_BEFORE_2.1> sudo dnf versionlock add .net-core

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

microsoft powershell core UPGRADE

Affected: >= 7.0 and < 7.0.7 · >= 7.1 and < 7.1.4

Fixed in: 7.0.7, 7.1.4

Safe to downgrade to: a release before 7.0

1. Check installed version

apt-cache policy powershell-core || rpm -q powershell-core || powershell-core --version

2. UPGRADE to 7.0.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade powershell-core

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade powershell-core

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 7.0 (Debian / Ubuntu)

apt-cache madison powershell-core sudo apt install powershell-core=<VERSION_BEFORE_7.0> sudo apt-mark hold powershell-core

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list powershell-core sudo dnf downgrade powershell-core-<VERSION_BEFORE_7.0> sudo dnf versionlock add powershell-core

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

microsoft visual studio 2017 UPGRADE

Affected: >= 15.0 and <= 15.9

Fixed in: newer than 15.9

Safe to downgrade to: a release before 15.0

1. Check installed version

apt-cache policy visual-studio-2017 || rpm -q visual-studio-2017 || visual-studio-2017 --version

2. UPGRADE to newer than 15.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade visual-studio-2017

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade visual-studio-2017

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 15.0 (Debian / Ubuntu)

apt-cache madison visual-studio-2017 sudo apt install visual-studio-2017=<VERSION_BEFORE_15.0> sudo apt-mark hold visual-studio-2017

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list visual-studio-2017 sudo dnf downgrade visual-studio-2017-<VERSION_BEFORE_15.0> sudo dnf versionlock add visual-studio-2017

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

microsoft visual studio 2019 UPGRADE

Affected: >= 16.0 and <= 16.10

Fixed in: newer than 16.10

Safe to downgrade to: a release before 16.0

1. Check installed version

apt-cache policy visual-studio-2019 || rpm -q visual-studio-2019 || visual-studio-2019 --version

2. UPGRADE to newer than 16.10 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade visual-studio-2019

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade visual-studio-2019

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 16.0 (Debian / Ubuntu)

apt-cache madison visual-studio-2019 sudo apt install visual-studio-2019=<VERSION_BEFORE_16.0> sudo apt-mark hold visual-studio-2019

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list visual-studio-2019 sudo dnf downgrade visual-studio-2019-<VERSION_BEFORE_16.0> sudo dnf versionlock add visual-studio-2019

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-34485?

.net: upgrade to newer than 5.0.8; .net core: upgrade to newer than 3.1.17; powershell core: upgrade to 7.0.7, 7.1.4. Exact commands for each OS are on this page.

Is CVE-2021-34485 being exploited?

CVE-2021-34485 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-34485 affect?

CVE-2021-34485 affects .net, .net core, powershell core. Severity is medium (CVSS 5.0). .NET Core and Visual Studio Information Disclosure Vulnerability

How urgent is CVE-2021-34485?

Priority 43/100. On your watchlist

Software pages

.NET vulnerabilities · Visual Studio vulnerabilities · PowerShell vulnerabilities

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References

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