# CVE-2026-61714: fluidsynth: FluidSynth is a software synthesizer based on the SoundFont 2 specifications

CVE-2026-61714 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-61714, released July 26, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-61714
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0014
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 18, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | fluidsynth Debian 13.5 (trixie) | 2.4.4+dfsg-1+deb13u3 | [DEBIAN-CVE-2026-61714](https://patchblox.com/security/data/fix/linux/debian-cve-2026-61714.md) | Jul 26, 2026 |
| Linux | fluidsynth Debian 14 | 2.5.6+dfsg-1 | [DEBIAN-CVE-2026-61714](https://patchblox.com/security/data/fix/linux/debian-cve-2026-61714.md) | Jul 26, 2026 |
| Linux | fluidsynth Ubuntu 22.04.1 LTS (jammy) | 2.2.5-1ubuntu0.1~esm1 | [fluidsynth 2.2.5-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-fluidsynth-2.2.5-1ubuntu0.1-esm1.md) | Oct 7, 2026 |
| Linux | fluidsynth Ubuntu 24.04.5 LTS (noble) | 2.3.4-1ubuntu0.1~esm1 | [fluidsynth 2.3.4-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-fluidsynth-2.3.4-1ubuntu0.1-esm1.md) | Oct 7, 2026 |
| Linux | fluidsynth Ubuntu 26.04.1 LTS (resolute) | 2.4.8+dfsg-1ubuntu0.1~esm1 | [fluidsynth 2.4.8+dfsg-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-fluidsynth-2.4.8-dfsg-1ubuntu0.1-esm1.md) | Sep 18, 2026 |
| Linux | libfluidsynth3 Ubuntu 22.04.1 LTS (jammy) | 2.2.5-1ubuntu0.1~esm1 | [libfluidsynth3 2.2.5-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libfluidsynth3-2.2.5-1ubuntu0.1-esm1.md) | Oct 7, 2026 |
| Linux | libfluidsynth3 Ubuntu 24.04.5 LTS (noble) | 2.3.4-1ubuntu0.1~esm1 | [libfluidsynth3 2.3.4-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfluidsynth3-2.3.4-1ubuntu0.1-esm1.md) | Oct 7, 2026 |
| Linux | libfluidsynth3 Ubuntu 26.04.1 LTS (resolute) | 2.4.8+dfsg-1ubuntu0.1~esm1 | [libfluidsynth3 2.4.8+dfsg-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfluidsynth3-2.4.8-dfsg-1ubuntu0.1-esm1.md) | Sep 18, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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