CVE-2026-58264FluidSynth: Heap-based buffer overrun

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 1.1.2 until 2.5.6, the FluidSynth command handler accepts a pitch_bend_range command whose channel argument is not bounds checked before the supplied value is written through the selected synth channel. An out-of-range channel can therefore cause an out-of-bounds heap write, leading to denial of service or possible code execution. The issue is remotely reachable when the TCP server is enabled through new_fluid_server() or fluidsynth -s, and it is locally reachable through malicious commands delivered to the FluidSynth shell on standard input. Applications that do not use the shell, command handler, or TCP server are not affected. This issue is fixed in version 2.5.6.

CVSS

9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness (CWE)

CWE-122

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

GitHub_M

NVD analysis

Deferred

Record last updated

Sep 21, 2026

First seen by InfoSec Signals

Oct 9, 2026

The CVE record on cve.org · NVD's entry

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