---
id: CVE-2026-61723
title: FluidSynth is a software synthesizer based on the SoundFont 2 specifications
summary: >-
  FluidSynth is a software synthesizer based on the SoundFont 2 specifications.
  From 2.5.0 until 2.5.6, the native DLS parser validates ptbl chunks with the
  unsigned expression cues * 4 + cbsize without checking whether the
  multiplication …
severity: medium
cvss: 6.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'
cwe:
  - CWE-190
vendor: FluidSynth
product: fluidsynth
affected:
  - 'fluidsynth >= 2.5.0, < 2.5.6'
published: '2026-09-18'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:25:27.050'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-61723'
references:
  - url: >-
      https://github.com/FluidSynth/fluidsynth/commit/a2ab32b9c3b9f8845b7254adea73c211f6c5a24c
    label: security-advisories@github.com
  - url: 'https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.6'
    label: security-advisories@github.com
  - url: >-
      https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-r4mc-v3p8-pv47
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
epss: 0.00184
epssPercentile: 0.07016
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-21T19:40:11.237880Z'
ingestedAt: '2026-09-18T20:51:25.676Z'
---

## Overview

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS parser validates ptbl chunks with the unsigned expression cues * 4 + cbsize without checking whether the multiplication and addition fit in 32 bits. A crafted DLS file can supply a large cues value that wraps the expression and passes the chunk-size check, causing poolcues.resize(cues) to request approximately four gigabytes and the parser to read billions of entries beyond the chunk boundary. The excessive allocation and invalid reads can cause denial of service. Builds with enable-native-dls set to OFF are not exposed. This issue is fixed in version 2.5.6.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.