# CVE-2026-65815: Microsoft Dynamics 365 deserialization of untrusted data in on-premises

Source: https://junglewise.ai/threats/cve-2026-65815-microsoft-dynamics-365-deserialization-of-untrusted-data-in-on  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-65815 · Severity: high · CVSS 8.8 · Published 2026-08-11

Microsoft Dynamics 365 on-premises is an enterprise business management system. A deserialization vulnerability allows authorized network users to execute arbitrary code on servers running this software, potentially compromising business data, operations, and customer information stored in the system.

Technologies: [Microsoft Dynamics 365](https://junglewise.ai/threats/technologies/dynamics-365). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-65815 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-65815 being exploited in the wild.

**How severe is CVE-2026-65815?** High severity, with a CVSS score of 8.8, published 11 August 2026.

**Which products and versions are affected?** Microsoft Dynamics 365 on-premises (specific versions not disclosed in advisory).

**Is there a fix for CVE-2026-65815?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-65815 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-65815?** Check whether you run Microsoft Dynamics 365 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a deserialization of untrusted data flaw in Microsoft Dynamics 365 on-premises. An authorized attacker can send specially crafted network traffic to trigger unsafe deserialization, leading to remote code execution. While authentication is required, the network-reachable attack vector means any authorized user with network access can exploit this. Patches are expected to be available through Microsoft's security updates.

## Affected products

- Microsoft Dynamics 365 on-premises (specific versions not disclosed in advisory)

## Timeline

- 2026-08-11: disclosed: CVE-2026-65815 published

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65815](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65815)

## Related threats

- [Microsoft Dynamics 365 code injection in code generation](https://junglewise.ai/threats/cve-2026-77908-microsoft-dynamics-365-code-injection-in-code-generation)
- [Microsoft Dynamics 365 deserialization of untrusted data](https://junglewise.ai/threats/cve-2026-65772-microsoft-dynamics-365-deserialization-of-untrusted-data)
- [Microsoft Dynamics 365 sensitive information disclosure](https://junglewise.ai/threats/cve-2026-66301-microsoft-dynamics-365-sensitive-information-disclosure)
- [Microsoft Dynamics 365 privilege escalation via improper access control](https://junglewise.ai/threats/cve-2026-47647-microsoft-dynamics-365-privilege-escalation-via-improper-access)
- [Microsoft Dynamics 365 code injection](https://junglewise.ai/threats/cve-2026-42833-microsoft-dynamics-365-code-injection)