CVE-2026-55944: Deserialization of untrusted data in Microsoft Dynamics NAV allows an unauthorized attacker to execute code ov

This week

CRITICAL 9.8REMOTEWATCHLISTDOWNGRADE

CVE-2026-55944 is a critical-severity flaw (CVSS 9.8) affecting dynamics nav. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Deserialization of untrusted data in Microsoft Dynamics NAV allows an unauthorized attacker to execute code over a network.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 25%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-07-14
Last modified	2026-10-24

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-14 18:18 UTCPublished CVE record published
2026-10-24 21:10 UTCUpdated Record last modified

microsoft dynamics nav DOWNGRADE

Affected: 2018

Fixed in: no fixed release known

Safe to downgrade to: a release before 2018

1. Check installed version

apt-cache policy dynamics-nav || rpm -q dynamics-nav || dynamics-nav --version

2. No fixed release: DOWNGRADE to a release before 2018 (Debian / Ubuntu)

apt-cache madison dynamics-nav sudo apt install dynamics-nav=<VERSION_BEFORE_2018> sudo apt-mark hold dynamics-nav

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

dnf --showduplicates list dynamics-nav sudo dnf downgrade dynamics-nav-<VERSION_BEFORE_2018> sudo dnf versionlock add dynamics-nav

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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · conda · FIXED · 26.9.4-2.fc46 · FEDORA-2026-09931756f1 · source

sudo dnf upgrade --advisory=FEDORA-2026-09931756f1

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-2026-55944?

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

Is CVE-2026-55944 being exploited?

CVE-2026-55944 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-2026-55944 affect?

CVE-2026-55944 affects dynamics nav. Severity is critical (CVSS 9.8). Deserialization of untrusted data in Microsoft Dynamics NAV allows an unauthorized attacker to execute code over a network.

How urgent is CVE-2026-55944?

Priority 66/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

References

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