FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.2.4 until 2.5.6, configuring synth.midi-channels above 16 allows the MIDI player to index _fluid_player_t::channel_isplaying outside its fixed-size heap allocation while tracking active channels. The resulting out-of-bounds reads and writes invoke undefined behavior and may compromise confidentiality, integrity, or availability. No crafted MIDI file is required because the unsafe condition is created by the channel-count configuration itself. Keeping synth.midi-channels at its default value of 16 avoids the vulnerable path. This issue is fixed in version 2.5.6.
History

Sat, 26 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Sun, 20 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
First Time appeared Fluidsynth
Fluidsynth fluidsynth
Vendors & Products Fluidsynth
Fluidsynth fluidsynth

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Description FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.2.4 until 2.5.6, configuring synth.midi-channels above 16 allows the MIDI player to index _fluid_player_t::channel_isplaying outside its fixed-size heap allocation while tracking active channels. The resulting out-of-bounds reads and writes invoke undefined behavior and may compromise confidentiality, integrity, or availability. No crafted MIDI file is required because the unsafe condition is created by the channel-count configuration itself. Keeping synth.midi-channels at its default value of 16 avoids the vulnerable path. This issue is fixed in version 2.5.6.
Title FluidSynth: Heap Buffer Overflow in MIDI Player
Weaknesses CWE-122
CWE-125
CWE-787
References
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-18T20:01:14.342Z

Updated: 2026-09-25T16:13:08.897Z

Reserved: 2026-07-10T18:51:13.920Z

Link: CVE-2026-61714

cve-icon Vulnrichment

Updated: 2026-09-25T16:13:04.679Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-18T20:17:18.270

Modified: 2026-09-25T17:17:09.700

Link: CVE-2026-61714

cve-icon Redhat

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