# CVE-2026-61720: fluidsynth: FluidSynth is a software synthesizer based on the SoundFont 2 specifications

CVE-2026-61720 is fixed in fluidsynth on 1 platform by DEBIAN-CVE-2026-61720 (version 2.5.6+dfsg-1), released July 26, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-61720
- Priority: Routine
- CVSS: 6.2 (medium)
- EPSS: 0.0018
- 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 2.5.0 until 2.5.6, the SF2 parser computes the DMOD modulator count as chunk.size / SF_MOD_SIZE - 1 without rejecting chunks smaller than one record. A crafted SF2 file containing a zero-sized DMOD chunk makes the unsigned subtraction wrap to UINT_MAX, and the parser then attempts billions of SFMod allocations. This exhausts process memory and causes denial of service. No workaround is available. This issue is fixed in version 2.5.6.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | fluidsynth Debian 14 | 2.5.6+dfsg-1 | [DEBIAN-CVE-2026-61720](https://patchblox.com/security/data/fix/linux/debian-cve-2026-61720.md) | Jul 26, 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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