FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS loader assigns file-controlled wsmp.loop_start and wsmp.loop_length values to samples without calling fluid_sample_validate() or fluid_sample_sanitize_loop(). A crafted DLS file can place sample loop points beyond the sample buffer, causing out-of-bounds reads during audio rendering, undefined behavior, possible memory disclosure, and denial of service. Builds compiled with the CMake option enable-native-dls set to OFF do not expose the affected parser. This issue is fixed in version 2.5.6.
History

Sun, 20 Sep 2026 02:15:00 +0000

Type Values Removed Values Added
First Time appeared Fluidsynth
Fluidsynth fluidsynth
Vendors & Products Fluidsynth
Fluidsynth fluidsynth

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Description FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS loader assigns file-controlled wsmp.loop_start and wsmp.loop_length values to samples without calling fluid_sample_validate() or fluid_sample_sanitize_loop(). A crafted DLS file can place sample loop points beyond the sample buffer, causing out-of-bounds reads during audio rendering, undefined behavior, possible memory disclosure, and denial of service. Builds compiled with the CMake option enable-native-dls set to OFF do not expose the affected parser. This issue is fixed in version 2.5.6.
Title FluidSynth: Heap-based buffer overrun for DLS samples
Weaknesses CWE-122
CWE-125
References
Metrics cvssV3_1

{'score': 8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-18T20:00:29.403Z

Updated: 2026-09-18T20:21:42.856Z

Reserved: 2026-07-10T18:51:13.920Z

Link: CVE-2026-61721

cve-icon Vulnrichment

Updated: 2026-09-18T20:21:39.282Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-18T20:17:18.567

Modified: 2026-09-23T18:12:04.247

Link: CVE-2026-61721

cve-icon Redhat

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