CVE-2026-55944 — Dynamics Nav
CRITICALCVE-2026-55944 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in microsoft dynamics nav. No vendor fix is recorded yet; mitigation options are listed below.
Deserialization of untrusted data in Microsoft Dynamics NAV allows an unauthorized attacker to execute code over a network.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55944.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-55944 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
Deserialization of untrusted data in Microsoft Dynamics NAV allows an unauthorized attacker to execute code over a network.
Affected Products
dynamics navmicrosoftDetection & mitigation playbook
Vendor / applianceDetect
Inventory every microsoft dynamics nav deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2026-55944 yet — track the microsoft dynamics nav advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2026-55944 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.