CVE-2026-58264

fluidsynth: FluidSynth is a software synthesizer based on the SoundFont 2 specifications

CVE-2026-58264 is fixed in 4 products on 1 platform, first by DEBIAN-CVE-2026-58264, released July 26, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

Urgent
CVSS
9.8
critical
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0059
48th percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
fluidsynth · Debian 13.5 (trixie) 2.4.4+dfsg-1+deb13u3 DEBIAN-CVE-2026-58264 Jul 26, 2026
fluidsynth · Debian 14 2.5.6+dfsg-1 DEBIAN-CVE-2026-58264 Jul 26, 2026
fluidsynth · Ubuntu 18.04.6 LTS (bionic) 1.1.9-1ubuntu0.1~esm1 fluidsynth 1.1.9-1ubuntu0.1~esm1 Oct 7, 2026
fluidsynth · Ubuntu 20.04 LTS (focal) 2.1.1-2ubuntu0.1~esm1 fluidsynth 2.1.1-2ubuntu0.1~esm1 Oct 7, 2026
fluidsynth · Ubuntu 22.04.1 LTS (jammy) 2.2.5-1ubuntu0.1~esm1 fluidsynth 2.2.5-1ubuntu0.1~esm1 Oct 7, 2026
fluidsynth · Ubuntu 24.04.5 LTS (noble) 2.3.4-1ubuntu0.1~esm1 fluidsynth 2.3.4-1ubuntu0.1~esm1 Oct 7, 2026
fluidsynth · Ubuntu 26.04.1 LTS (resolute) 2.4.8+dfsg-1ubuntu0.1~esm1 fluidsynth 2.4.8+dfsg-1ubuntu0.1~esm1 Sep 18, 2026
libfluidsynth1 · Ubuntu 18.04.6 LTS (bionic) 1.1.9-1ubuntu0.1~esm1 libfluidsynth1 1.1.9-1ubuntu0.1~esm1 Oct 7, 2026
libfluidsynth2 · Ubuntu 20.04 LTS (focal) 2.1.1-2ubuntu0.1~esm1 libfluidsynth2 2.1.1-2ubuntu0.1~esm1 Oct 7, 2026
libfluidsynth3 · Ubuntu 22.04.1 LTS (jammy) 2.2.5-1ubuntu0.1~esm1 libfluidsynth3 2.2.5-1ubuntu0.1~esm1 Oct 7, 2026
libfluidsynth3 · Ubuntu 24.04.5 LTS (noble) 2.3.4-1ubuntu0.1~esm1 libfluidsynth3 2.3.4-1ubuntu0.1~esm1 Oct 7, 2026
libfluidsynth3 · Ubuntu 26.04.1 LTS (resolute) 2.4.8+dfsg-1ubuntu0.1~esm1 libfluidsynth3 2.4.8+dfsg-1ubuntu0.1~esm1 Sep 18, 2026

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