High · published December 24, 2025
⚡ A sneaky race condition in FluidSynth could lead to a heap-based use-after-free situation! Imagine multiple musicians trying to pack up their instruments at once, and one accidentally knocks over a crucial piece — chaos ensues! 🎶 Think of it like a busy restaurant where several chefs are trying to prepare dishes simultaneously. If one chef starts clearing their station while another is still using ingredients from it, things can get messy — and someone might end up with a dish cooked with spoiled items! In this scenario, an attacker could exploit the race condition to access or manipulate freed memory, potentially leading to crashes or arbitrary code execution while synthesizing audio. This could disrupt services or introduce vulnerabilities that could be exploited in the system, making it critical to address this swiftly!
Think of it like a busy restaurant where several chefs are trying to prepare dishes simultaneously. If one chef starts clearing their station while another is still using ingredients from it, things can get messy — and someone might end up with a dish cooked with spoiled items! This vulnerability occurs during the unloading of a DLS file in FluidSynth versions 2.5.0 to before 2.5.2, allowing a concurrently running thread to use freed memory if the synthesizer is destroyed while still using samples from the DLS file. Essentially, this can result in unpredictable behavior or crashes.
In this scenario, an attacker could exploit the race condition to access or manipulate freed memory, potentially leading to crashes or arbitrary code execution while synthesizing audio. This could disrupt services or introduce vulnerabilities that could be exploited in the system, making it critical to address this swiftly! To fix this issue, update to FluidSynth version 2.5.2 as soon as possible to eliminate the race condition. If you’re compiling FluidSynth yourself, consider disabling native DLS support to avoid triggering the vulnerability until you can patch. Always review your code for any concurrent operations that could lead to similar issues! You've got this! By taking these steps, you'll secure your synthesizer and make the internet a safer place for sound! 🛡️
| Product | Versions | Fixed in |
|---|---|---|
| fluidsynth/fluidsynth | ≥ 2.5.0, < 2.5.2 | 2.5.2 |