CVE-2026-86926

Memory corruption via malformed database block parsing

Published Sep 23, 2026 · Updated Sep 23, 2026

Heap buffer overflow in Claris FileMaker Server before 26.0.3 allows attackers to corrupt memory via a crafted .fmp12 database file. The database engine's block-parsing routine overruns a heap allocation while decoding attacker-controlled block data from the file. Exploitation requires the server to parse the crafted database and can result in arbitrary code execution in the server process.

CVSS severityUnavailable
Unscored
EPSS probability0.13%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in Claris FileMaker Server before 26.0.3 allows attackers to corrupt memory via a crafted .fmp12 database file. The database engine's block-parsing routine overruns a heap allocation while decoding attacker-controlled block data from the file. Exploitation requires the server to parse the crafted database and can result in arbitrary code execution in the server process.

The record

CVE
CVE-2026-86926
Published
Sep 23, 2026
Updated
Sep 23, 2026
Vendor
Claris
Product
FileMaker Server
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <26.0.3

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Claris · FileMaker Serverversion=0 <26.0.3

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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