# CVE-2026-87692: Microsoft Exchange Server deserialization privilege elevation

Source: https://junglewise.ai/threats/cve-2026-87692-deserialization-of-untrusted-data-in-microsoft-exchange-server  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-29  
License: CC BY 4.0 with a link back

CVE-2026-87692 · Severity: high · CVSS 7.8 · Published 2026-10-13

Microsoft Exchange Server, which handles corporate email and calendar services, contains a flaw that allows an authorized user to execute code with elevated privileges on the affected system. An attacker with valid Exchange credentials could exploit this to gain administrative control of the email infrastructure.

Technologies: [Microsoft Exchange Server](https://junglewise.ai/threats/technologies/exchange-server), [Microsoft Exchange Server Subscription Edition](https://junglewise.ai/threats/technologies/exchange-server-subscription-edition). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-87692 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-87692 being exploited in the wild.

**How severe is CVE-2026-87692?** High severity, with a CVSS score of 7.8, published 13 October 2026.

**Which products and versions are affected?** Microsoft Exchange Server.

**Is there a fix for CVE-2026-87692?** 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-2026-87692 attacked?** It is attacked with local access, in a hosted service.

**Am I affected by CVE-2026-87692?** Check whether you run Microsoft Exchange Server or Microsoft Exchange Server Subscription Edition. 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

A deserialization flaw in Microsoft Exchange Server allows an authenticated attacker to deserialize untrusted data, leading to local privilege escalation. The vulnerability requires valid credentials to exploit and affects the Exchange Server process, enabling an authenticated user to execute arbitrary code with system privileges.

## Affected products

- Microsoft Exchange Server

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87692](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87692)

## Related threats

- [Microsoft Exchange Server improper access control spoofing](https://junglewise.ai/threats/cve-2026-118208-improper-access-control-in-microsoft-exchange-server-allows-an)
- [Microsoft Exchange Server improper input validation code execution](https://junglewise.ai/threats/cve-2026-118207-improper-input-validation-in-microsoft-exchange-server-allows-an)
- [Microsoft Exchange Server weak authentication privilege elevation](https://junglewise.ai/threats/cve-2026-118157-weak-authentication-in-microsoft-exchange-server-allows-an)
- [Microsoft Exchange Server privilege elevation via untrusted security decision input](https://junglewise.ai/threats/cve-2026-118154-reliance-on-untrusted-inputs-in-a-security-decision-in-microsoft)
- [Microsoft Exchange Server algorithmic complexity denial of service](https://junglewise.ai/threats/cve-2026-118153-inefficient-algorithmic-complexity-in-microsoft-exchange-server)