CVE-2026-58641: Integer overflow or wraparound in .NET allows an unauthorized attacker to elevate privileges locally.

This month

HIGH 7.8WATCHLISTUPGRADE

CVE-2026-58641 is a high-severity flaw (CVSS 7.8) affecting .net. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer overflow or wraparound in .NET allows an unauthorized attacker to elevate privileges locally.

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-190
Published	2026-08-11
Last modified	2026-09-03

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-09-03 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-11 17:18 UTCPublished CVE record published
2026-09-03 16:17 UTCUpdated Record last modified

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.

Quick answers

How do I fix CVE-2026-58641?

.net: upgrade to 8.0.30, 9.0.19, 10.0.11. Exact commands for each OS are on this page.

Is CVE-2026-58641 being exploited?

CVE-2026-58641 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-2026-58641 affect?

CVE-2026-58641 affects .net. Severity is high (CVSS 7.8). Integer overflow or wraparound in .NET allows an unauthorized attacker to elevate privileges locally.

How urgent is CVE-2026-58641?

Priority 42/100. High severity; On your watchlist

Related CVEs

CVE-2026-32178 HIGH 7.5 UPGRADE UPGRADE Improper neutralization of special elements in .NET allows an unauthorized attacker to perform spoofing over a
CVE-2026-26171 HIGH 7.5 UPGRADE UPGRADE Uncontrolled resource consumption in .NET allows an unauthorized attacker to deny service over a network.
CVE-2026-32203 HIGH 7.5 UPGRADE UPGRADE Stack-based buffer overflow in .NET and Visual Studio allows an unauthorized attacker to deny service over a n
CVE-2026-42899 HIGH 7.5 UPGRADE Loop with unreachable exit condition ('infinite loop') in ASP.NET Core allows an unauthorized attacker to deny
CVE-2026-35433 HIGH 7.3 DOWNGRADE UPGRADE Improper input validation in .NET allows an unauthorized attacker to elevate privileges locally.

References

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