# CVE-2026-86934: FileMaker Server authorization bypass in Web Publishing Engine

Source: https://junglewise.ai/threats/cve-2026-86934-an-authorization-bypass-vulnerability-in-the-filemaker-server-web  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-23. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-86934 · Severity: critical · CVSS 9.1 · Published 2026-09-23

FileMaker Server's Web Publishing Engine allows attackers to bypass security restrictions on XML-based web publishing interfaces by crafting requests with special headers. This vulnerability could allow unauthorized access to sensitive data through the XML Web Publishing interface even when administrators have intentionally disabled it.

Technologies: [Claris FileMaker Server](https://junglewise.ai/threats/technologies/filemaker-server). Vendors: [Claris](https://junglewise.ai/threats/vendors/claris).

## Quick answers

**Is CVE-2026-86934 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86934 being exploited in the wild.

**How severe is CVE-2026-86934?** Critical severity, with a CVSS score of 9.1, published 23 September 2026.

**Which products and versions are affected?** Claris FileMaker Server before 26.0.3.

**Is there a fix for CVE-2026-86934?** A patch was published on 2026-09-23: addressed in FileMaker Server 26.0.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-86934 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-86934?** Check whether you run Claris FileMaker Server 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

An authorization bypass in FileMaker Server's Web Publishing Engine permits requests containing an extended privilege header to circumvent the disabled Custom Web Publishing with XML setting and gain access to the XML Web Publishing interface. The vulnerability requires network access to the Web Publishing Engine and is addressed in FileMaker Server 26.0.3 and later.

## Affected products

- Claris FileMaker Server before 26.0.3

## Timeline

- 2026-09-23: disclosed
- 2026-09-23: patched: addressed in FileMaker Server 26.0.3

## References

- [https://support.claris.com/s/answerview?anum=000049217&language=en_US](https://support.claris.com/s/answerview?anum=000049217&language=en_US)

## Related threats

- [FileMaker Server out-of-bounds read in image processing](https://junglewise.ai/threats/cve-2026-86930-an-out-of-bounds-read-vulnerability-in-filemaker-server-for-linux)
- [Claris FileMaker Server heap buffer overflow in database block parsing](https://junglewise.ai/threats/cve-2026-86926-a-heap-buffer-overflow-vulnerability-in-the-filemaker-server)
- [Claris FileMaker Server code execution in Open Source LLM setup](https://junglewise.ai/threats/cve-2026-43752-claris-filemaker-server-code-execution-in-open-source-llm-setup)