CVE-2026-67636: Out-of-bounds read in SQL Server allows an unauthorized attacker to execute code over a network.

This month

CRITICAL 9.0REMOTEWATCHLISTUPGRADEUPGRADEUPGRADE

CVE-2026-67636 is a critical-severity flaw (CVSS 9.0) affecting sql server 2019, sql server 2022, sql server 2025. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Out-of-bounds read in SQL Server allows an unauthorized attacker to execute code over a network.

Why this priority

Critical severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.0 (Critical)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 47%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-09-08
Last modified	2026-09-17

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-09-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-08 18:18 UTCPublished CVE record published
2026-09-17 20:17 UTCUpdated Record last modified

microsoft sql server 2019 UPGRADE

Affected: < 15.0.2190.7 · >= 15.0.4003.23 and < 15.0.4490.9

Fixed in: 15.0.2190.7, 15.0.4490.9

Safe to downgrade to: a release before 15.0.4003.23

1. Check installed version

apt-cache policy sql-server-2019 || rpm -q sql-server-2019 || sql-server-2019 --version

2. UPGRADE to 15.0.2190.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sql-server-2019

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sql-server-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 15.0.4003.23 (Debian / Ubuntu)

apt-cache madison sql-server-2019 sudo apt install sql-server-2019=<VERSION_BEFORE_15.0.4003.23> sudo apt-mark hold sql-server-2019

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

dnf --showduplicates list sql-server-2019 sudo dnf downgrade sql-server-2019-<VERSION_BEFORE_15.0.4003.23> sudo dnf versionlock add sql-server-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.

microsoft sql server 2022 UPGRADE

Affected: < 16.0.1200.5 · >= 16.0.4003.1 and < 16.0.4275.2

Fixed in: 16.0.1200.5, 16.0.4275.2

Safe to downgrade to: a release before 16.0.4003.1

1. Check installed version

apt-cache policy sql-server-2022 || rpm -q sql-server-2022 || sql-server-2022 --version

2. UPGRADE to 16.0.1200.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sql-server-2022

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sql-server-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 16.0.4003.1 (Debian / Ubuntu)

apt-cache madison sql-server-2022 sudo apt install sql-server-2022=<VERSION_BEFORE_16.0.4003.1> sudo apt-mark hold sql-server-2022

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

dnf --showduplicates list sql-server-2022 sudo dnf downgrade sql-server-2022-<VERSION_BEFORE_16.0.4003.1> sudo dnf versionlock add sql-server-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 sql server 2025 UPGRADE

Affected: < 17.0.1135.8 · >= 17.0.4006.2 and < 17.0.4085.5

Fixed in: 17.0.1135.8, 17.0.4085.5

Safe to downgrade to: a release before 17.0.4006.2

1. Check installed version

apt-cache policy sql-server-2025 || rpm -q sql-server-2025 || sql-server-2025 --version

2. UPGRADE to 17.0.1135.8 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sql-server-2025

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sql-server-2025

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 17.0.4006.2 (Debian / Ubuntu)

apt-cache madison sql-server-2025 sudo apt install sql-server-2025=<VERSION_BEFORE_17.0.4006.2> sudo apt-mark hold sql-server-2025

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

dnf --showduplicates list sql-server-2025 sudo dnf downgrade sql-server-2025-<VERSION_BEFORE_17.0.4006.2> sudo dnf versionlock add sql-server-2025

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-2026-67636?

sql server 2019: upgrade to 15.0.2190.7, 15.0.4490.9; sql server 2022: upgrade to 16.0.1200.5, 16.0.4275.2; sql server 2025: upgrade to 17.0.1135.8, 17.0.4085.5. Exact commands for each OS are on this page.

Is CVE-2026-67636 being exploited?

CVE-2026-67636 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-2026-67636 affect?

CVE-2026-67636 affects sql server 2019, sql server 2022, sql server 2025. Severity is critical (CVSS 9.0). Out-of-bounds read in SQL Server allows an unauthorized attacker to execute code over a network.

How urgent is CVE-2026-67636?

Priority 55/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Microsoft SQL Server vulnerabilities

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References

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