PatchTheCVECVE-2026-62899: Inconsistent interpretation of http requests ('http request/response smuggling') in .NET allows an unauthorize
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MEDIUM 5.9REMOTEWATCHLISTUPGRADEUPGRADEUPGRADE
CVE-2026-62899 is a medium-severity flaw (CVSS 5.9) affecting visual studio 2022, visual studio 2026, .net. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Inconsistent interpretation of http requests ('http request/response smuggling') in .NET allows an unauthorized attacker to bypass a security feature over a network.
Why this priority
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 5.9 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.7% (top 45%) |
| CISA exploited list | No |
| Weakness | CWE-444 |
| Published | 2026-08-11 |
| Last modified | 2026-08-14 |
Publisher (CNA): Microsoft Corporation · Vendor: microsoft
Last updated 2026-08-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
microsoft visual studio 2022 UPGRADE
Affected: >= 17.14.0 and < 17.14.38
Fixed in: 17.14.38
Safe to downgrade to: a release before 17.14.0
1. Check installed version
apt-cache policy visual-studio-2022 || rpm -q visual-studio-2022 || visual-studio-2022 --version
2. UPGRADE to 17.14.38 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade visual-studio-2022
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade visual-studio-2022
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 17.14.0 (Debian / Ubuntu)
apt-cache madison visual-studio-2022
sudo apt install visual-studio-2022=<VERSION_BEFORE_17.14.0>
sudo apt-mark hold visual-studio-2022
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list visual-studio-2022
sudo dnf downgrade visual-studio-2022-<VERSION_BEFORE_17.14.0>
sudo dnf versionlock add visual-studio-2022
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 2026 UPGRADE
Affected: >= 18.8.0 and < 18.8.3
Fixed in: 18.8.3
Safe to downgrade to: a release before 18.8.0
1. Check installed version
apt-cache policy visual-studio-2026 || rpm -q visual-studio-2026 || visual-studio-2026 --version
2. UPGRADE to 18.8.3 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade visual-studio-2026
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade visual-studio-2026
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 18.8.0 (Debian / Ubuntu)
apt-cache madison visual-studio-2026
sudo apt install visual-studio-2026=<VERSION_BEFORE_18.8.0>
sudo apt-mark hold visual-studio-2026
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list visual-studio-2026
sudo dnf downgrade visual-studio-2026-<VERSION_BEFORE_18.8.0>
sudo dnf versionlock add visual-studio-2026
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 UPGRADE
Affected: >= 8.0.0 and < 8.0.30 · >= 9.0.0 and < 9.0.19 · >= 10.0.0 and < 10.0.11
Fixed in: 8.0.30, 9.0.19, 10.0.11
Safe to downgrade to: a release before 8.0.0
1. Check installed version
apt-cache policy .net || rpm -q .net || .net --version
2. UPGRADE to 8.0.30 (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 8.0.0 (Debian / Ubuntu)
apt-cache madison .net
sudo apt install .net=<VERSION_BEFORE_8.0.0>
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_8.0.0>
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.
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.
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-2026-62899?
visual studio 2022: upgrade to 17.14.38; visual studio 2026: upgrade to 18.8.3; .net: upgrade to 8.0.30, 9.0.19, 10.0.11. Exact commands for each OS are on this page.
Is CVE-2026-62899 being exploited?
CVE-2026-62899 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-2026-62899 affect?
CVE-2026-62899 affects visual studio 2022, visual studio 2026, .net. Severity is medium (CVSS 5.9). Inconsistent interpretation of http requests ('http request/response smuggling') in .NET allows an unauthorized attacker to bypass a security feature over a network.
How urgent is CVE-2026-62899?
Priority 44/100. Remotely exploitable, no login, no user action; On your watchlist
Software pages
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