CVE-2025-68617

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From versions 2.5.0 to before 2.5.2, a race condition during unloading of a DLS file can trigger a heap-based use-after-free. A concurrently running thread may be pending to unload a DLS file, leading to use of freed memory, if the synthesizer is being concurrently destroyed, or samples of the (unloaded) DLS file are concurrently used to synthesize audio. This issue has been patched in version 2.5.2. The problem will not occur, when explicitly unloading a DLS file (before synth destruction), provided that at the time of unloading, no samples of the respective file are used by active voices. The problem will not occur in versions of FluidSynth that have been compiled without native DLS support.

Published Dec 26, 2025

https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-ffw2-xvvp-39ch

CVSS ScoreHigh

7.0

Ecosystem	Package	Version

Ecosystem	Package	Version

Vulnerabilities

CVE-2025-68617

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From versions 2.5.0 to before 2.5.2, a race condition during unloading of a DLS file can trigger a heap-based use-after-free. A concurrently running thread may be pending to unload a DLS file, leading to use of freed memory, if the synthesizer is being concurrently destroyed, or samples of the (unloaded) DLS file are concurrently used to synthesize audio. This issue has been patched in version 2.5.2. The problem will not occur, when explicitly unloading a DLS file (before synth destruction), provided that at the time of unloading, no samples of the respective file are used by active voices. The problem will not occur in versions of FluidSynth that have been compiled without native DLS support.

Published Dec 26, 2025

https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-ffw2-xvvp-39ch

CVSS ScoreHigh

7.0


rpm	fluidsynth	2.5.1-1.el10_2
rpm	fluidsynth	2.5.1-1.el9
rpm	fluidsynth-debuginfo	2.5.1-1.el10_2
rpm	fluidsynth-debuginfo	2.5.1-1.el9
rpm	fluidsynth-debugsource	2.5.1-1.el10_2
rpm	fluidsynth-debugsource	2.5.1-1.el9
rpm	fluidsynth-devel	2.5.1-1.el10_2
rpm	fluidsynth-devel	2.5.1-1.el9
rpm	fluidsynth-libs	2.5.1-1.el10_2
rpm	fluidsynth-libs	2.5.1-1.el9
rpm	fluidsynth-libs-debuginfo	2.5.1-1.el10_2
rpm	fluidsynth-libs-debuginfo	2.5.1-1.el9

Ecosystem	Package	Version


rpm	fluidsynth	2.5.1-1.el10_2
rpm	fluidsynth	2.5.1-1.el9
rpm	fluidsynth-debuginfo	2.5.1-1.el10_2
rpm	fluidsynth-debuginfo	2.5.1-1.el9
rpm	fluidsynth-debugsource	2.5.1-1.el10_2
rpm	fluidsynth-debugsource	2.5.1-1.el9
rpm	fluidsynth-devel	2.5.1-1.el10_2
rpm	fluidsynth-devel	2.5.1-1.el9
rpm	fluidsynth-libs	2.5.1-1.el10_2
rpm	fluidsynth-libs	2.5.1-1.el9
rpm	fluidsynth-libs-debuginfo	2.5.1-1.el10_2
rpm	fluidsynth-libs-debuginfo	2.5.1-1.el9

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CVE-2025-68617

CVE-2025-68617