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CVE-2025-68617— Use after free in fluidsynth

Quick assessment

Affected
FluidSynth fluidsynth
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

fluidsynth是fluidsynth开源的一个应用系统。用于通过使用SoundFont通过读取和处理MIDI输入设备中的MIDI事件来生成音频。 fluidsynth 2.5.2之前版本存在资源管理错误漏洞，该漏洞源于卸载DLS文件时存在竞争条件，可能触发基于堆的释放后重用。

CVSS 7.0 · High EPSS 0.21% · P11

Possible ATT&CK Techniques 1 AI

T1211 · Exploitation for Stealth
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I. Basic Information for CVE-2025-68617

Vulnerability Information
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Vulnerability Title
Use after free in fluidsynth
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
释放后使用
Source: CVE Program / CVE List V5
Vulnerability Title
fluidsynth 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
fluidsynth是fluidsynth开源的一个应用系统。用于通过使用SoundFont通过读取和处理MIDI输入设备中的MIDI事件来生成音频。 fluidsynth 2.5.2之前版本存在资源管理错误漏洞，该漏洞源于卸载DLS文件时存在竞争条件，可能触发基于堆的释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
FluidSynth fluidsynth >= 2.5.0, < 2.5.2 -

II. Public POCs for CVE-2025-68617

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 10411 chars
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
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III. Intelligence Information for CVE-2025-68617

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Patches & Fixes for CVE-2025-68617 (2)

Vendor Advisories for CVE-2025-68617 (1)

Other References for CVE-2025-68617 (2)

IV. Related Vulnerabilities

Same product: fluidsynth
Same vendor: FluidSynth
Same weakness: CWE-416

V. Comments for CVE-2025-68617

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