Microsoft Dynamics 365 is widely used in enterprises; an authenticated deserialization RCE can lead to server compromise, data loss, and major operational disruption.
CVE-2026-65815
Authenticated deserialization RCE in Microsoft Dynamics 365 (on-premises).
Is CVE-2026-65815 being exploited?
Not confirmed. CVE-2026-65815 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.93% probability of exploitation in the next 30 days.
How severe is CVE-2026-65815?
CVE-2026-65815 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-65815?
Yes. A fix has been recorded for CVE-2026-65815. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-65815 affect?
CVE-2026-65815 affects Microsoft Dynamics 365 (on-premises). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-65815?
Apply vendor patch/mitigations ASAP; restrict access, monitor logs, and isolate affected hosts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker can execute arbitrary code remotely via deserialization, enabling full server compromise, data exfiltration, or lateral movement.
Immediate action required
- affected>= 9.0 and < 9.1.0047.0006
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.