CVE-2026-40417: Weak authentication in Dynamics Business Central allows an authorized attacker to elevate privileges locally.

Routine

HIGH 7.8WATCHLISTDOWNGRADE

CVE-2026-40417 is a high-severity flaw (CVSS 7.8) affecting dynamics 365 business central. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Weak authentication in Dynamics Business Central allows an authorized attacker to elevate privileges locally.

Why this priority

High severity
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-1390
Published	2026-05-12
Last modified	2026-10-26

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-12 18:17 UTCPublished CVE record published
2026-10-26 00:10 UTCUpdated Record last modified

microsoft dynamics 365 business central DOWNGRADE

Affected: 2024 release_wave_2 · 2025 release_wave_1 · 2025 release_wave_2 · 2026 release_wave_1

Fixed in: no fixed release known

Safe to downgrade to: a release before 2024

1. Check installed version

apt-cache policy dynamics-365-business-central || rpm -q dynamics-365-business-central || dynamics-365-business-central --version

2. No fixed release: DOWNGRADE to a release before 2024 (Debian / Ubuntu)

apt-cache madison dynamics-365-business-central sudo apt install dynamics-365-business-central=<VERSION_BEFORE_2024> sudo apt-mark hold dynamics-365-business-central

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list dynamics-365-business-central sudo dnf downgrade dynamics-365-business-central-<VERSION_BEFORE_2024> sudo dnf versionlock add dynamics-365-business-central

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-2026-40417?

dynamics 365 business central: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-40417 being exploited?

CVE-2026-40417 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-2026-40417 affect?

CVE-2026-40417 affects dynamics 365 business central. Severity is high (CVSS 7.8). Weak authentication in Dynamics Business Central allows an authorized attacker to elevate privileges locally.

How urgent is CVE-2026-40417?

Priority 37/100. High severity; On your watchlist

References

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