CVE-2025-46294: Claris FileMaker Server · The IIS Shortname Vulnerability exploits how Microsoft IIS handles legacy 8.3 short filenames, allowing attackers to infer the existence of files or directories by crafting requests with the tilde (~) character.
Affects Claris FileMaker ServerSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium.
Data as of 26 Oct 2026, 08:30 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 14% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 16 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
1. Upgrade Claris FileMaker Server to version 22.0.4 or later, which includes the option to disable IIS short filename enumeration. 2. Configure the Windows registry key NtfsDisable8dot3NameCreation to disable 8.3 name creation on volumes hosting FileMaker Server data, preventing IIS from generating or recognizing short filenames. 3. Review IIS server configurations to limit or block HTTP requests containing tilde (~) characters if feasible, using web application firewalls or URL filtering rules. 4. Conduct regular security audits and monitoring for unusual HTTP requests that attempt to enumerate files via shortname patterns. 5. Educate system administrators about the risks of legacy 8.3 filename support and encourage disabling it where compatibility is not required. 6. Implement network segmentation and least privilege principles to limit exposure of FileMaker Server instances to untrusted networks. 7. Maintain up-to-date backups and incident response plans to quickly address any potential exploitation attempts.
Description
CVE-2025-46294 is a medium-severity vulnerability affecting Claris FileMaker Server that leverages Microsoft IIS's handling of legacy 8.3 short filenames. Attackers can exploit this by sending crafted requests containing the tilde (~) character to infer the existence of files or directories on the server, potentially revealing sensitive information. The vulnerability does not allow modification or deletion of data, nor does it require authentication or user interaction. It primarily impacts confidentiality by enabling information disclosure. FileMaker Server 22.0.4 addresses this issue by providing an option to disable IIS short filename enumeration via the NtfsDisable8dot3NameCreation registry setting. European organizations using vulnerable versions of FileMaker Server on IIS should apply this update promptly. Countries with significant adoption of Microsoft IIS and FileMaker Server, such as Germany, the UK, France, and the Netherlands, are more likely to be affected.