FluidSynth up to 2.5.5 MIDI Player synth.midi-channels memory corruption

Summaryinfo

A vulnerability classified as problematic was found in FluidSynth up to 2.5.5. This vulnerability affects unknown code of the component MIDI Player. Executing a manipulation of the argument synth.midi-channels can lead to memory corruption. This vulnerability is handled as CVE-2026-61714. It is possible to launch the attack on the local host. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in FluidSynth up to 2.5.5. It has been declared as problematic. This vulnerability affects an unknown function of the component MIDI Player. The manipulation of the argument synth.midi-channels with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability was named CVE-2026-61714 since 07/10/2026. The exploitation appears to be easy. Local access is required to approach this attack. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

Upgrading to version 2.5.6 eliminates this vulnerability.

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Productinfo

Name

• FluidSynth

Version

• 2.5.0
• 2.5.1
• 2.5.2
• 2.5.3
• 2.5.4
• 2.5.5

Website

• Product: https://github.com/FluidSynth/fluidsynth/

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