Auth bypass in Claris Filemaker Server

CVE-2026-86934

An authorization bypass vulnerability in the FileMaker Server Web Publishing Engine allowed requests containing an extended privilege header to bypass the disabled Custom Web Publishing with XML setting and access the XML Web Publishing interface. This vulnerability is addressed in FileMaker Server version 26.0.3.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (24.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-86934: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-86934?
CVE-2026-86934 is a critical-severity vulnerability in Claris Filemaker Server, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 9.1/10. Published 2026-09-23.
How severe is CVE-2026-86934?
Critical severity. CVSS v3 base score is 9.1 out of 10.