# CVE-2026-69355: Microsoft Exchange Server external control of file name or path

Source: https://junglewise.ai/threats/cve-2026-69355-microsoft-exchange-server-external-control-of-file-name-or-path  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-08. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-69355 · Severity: high · CVSS 8.8 · Published 2026-09-08

Microsoft Exchange Server is a widely-deployed email and collaboration platform used by enterprises to manage corporate communications. A vulnerability in file path handling allows an authorized attacker to execute arbitrary code remotely on affected servers, potentially leading to complete compromise of the email system and access to sensitive business communications.

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

## Quick answers

**Is CVE-2026-69355 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-69355 being exploited in the wild.

**How severe is CVE-2026-69355?** High severity, with a CVSS score of 8.8, published 8 September 2026.

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

**Is there a fix for CVE-2026-69355?** A patch was published: Security update released by Microsoft Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-69355 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-69355?** Check whether you run Microsoft Exchange Server. 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

This vulnerability is an external control of file name or path issue (CWE-426 class) in Microsoft Exchange Server. An authorized attacker can exploit improper file path validation to execute arbitrary code with the privileges of the Exchange process. The attack requires network connectivity to an affected Exchange Server and prior authentication; no additional user interaction is needed. Successful exploitation grants the attacker remote code execution on the server, enabling full system compromise. Microsoft has released security updates to address this vulnerability.

## Affected products

- Microsoft Exchange Server

## Timeline

- 2026-09-08: disclosed
- patched: Security update released by Microsoft

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69355](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69355)

## 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)