# CVE-2026-87695: Microsoft Exchange Server privilege escalation via untrusted control sphere

Source: https://junglewise.ai/threats/cve-2026-87695-inclusion-of-functionality-from-untrusted-control-sphere-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-27  
License: CC BY 4.0 with a link back

CVE-2026-87695 · Severity: high · CVSS 7.8 · Published 2026-10-13

Microsoft Exchange Server, which handles email and calendar services for organizations, contains a vulnerability that allows an authorized attacker to gain elevated privileges on the server. An attacker with valid credentials could exploit this to gain higher-level access, potentially compromising email data and administrative functions across the organization.

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-2026-87695 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-87695 being exploited in the wild.

**How severe is CVE-2026-87695?** 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-2026-87695?** 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-2026-87695 attacked?** It is attacked with local access, in a hosted service.

**Am I affected by CVE-2026-87695?** 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

The vulnerability stems from the inclusion of functionality from an untrusted control sphere in Exchange Server. An authenticated attacker can exploit this to perform privilege escalation locally on the affected system. The attack requires prior authentication or authorization, limiting the exposure to insider threats or attackers who have compromised valid credentials.

## Affected products

- Microsoft Exchange Server

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87695](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87695)

## 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)