Critical Access control

CVE-2026-86934 — Authorization Bypass Through User-Controlled Key (IDOR) in Claris Filemaker Server

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.

Published Sep 23, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database · CNA: product-security@apple.com

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Claris

Filemaker Server

CVSS base

9.1

Critical · 1 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Claris Filemaker Server).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Claris	Filemaker Server	< 26.0.3	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
9.1	CVSS 3.1	Critical	3.9	5.2	134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-639 · Authorization Bypass Through User-Controlled Key (IDOR)

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Audit administrative actions and access to resources outside each user’s normal pattern.

web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
CVSS changed · 9.1
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 23, 2026 · product-security@apple.com

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

support.claris.com/s/answerview
Vendor Advisory, NIST National Vulnerability Database

Elsewhere on this site

Claris
every CVE for this vendor

Access control
same class

CWE-639
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-86926 Heap-based Buffer Overflow in Claris Filemaker Server 22d
Critical CVE-2026-86930 Out-of-bounds Read in Claris Filemaker Server 22d
Medium CVE-2026-43752 Unrestricted Upload of File with Dangerous Type in Claris Filemaker Server Jul 9, 2026
Medium CVE-2025-46320 Cross-site Scripting (XSS) in Claris Filemaker Server Feb 24, 2026
Medium CVE-2025-46294 Exposure of Sensitive Information in Claris Filemaker Server Dec 16, 2025
Critical CVE-2025-46295 Code Injection in Claris Filemaker Server Dec 16, 2025

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-86934 is "Authorization Bypass Through User-Controlled Key (IDOR) in Claris Filemaker Server", rated Critical. It affects Filemaker Server (Claris); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.1 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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