CVE-2025-56225Public exploitNetwork attack vector

Service interrupt via null preset dereference

Published Jan 9, 2026 · Updated Jan 9, 2026

Null pointer dereference in FluidSynth 2.4.6 and earlier allows attackers to crash the synthesizer by loading a crafted MIDI file. In mono or legato mode, a note-off path calls fluid_synth_noteon_monopoly_legato with no preset assigned and dereferences the channel's null preset pointer. Processing must reach that channel state; the demonstrated result is a segmentation fault and service interrupt, not data access or modification.

CVSS severity7.5
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in FluidSynth 2.4.6 and earlier allows attackers to crash the synthesizer by loading a crafted MIDI file. In mono or legato mode, a note-off path calls fluid_synth_noteon_monopoly_legato with no preset assigned and dereferences the channel's null preset pointer. Processing must reach that channel state; the demonstrated result is a segmentation fault and service interrupt, not data access or modification.

The record

CVE
CVE-2025-56225
Published
Jan 9, 2026
Updated
Jan 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 9, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

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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