CVE-2026-61720

Published: Sep 18, 2026Modified: Sep 24, 2026Deferred

6.2

Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitability: 2.5 / Impact: 3.6

Source: security-advisories@github.com (Secondary)

Description

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the SF2 parser computes the DMOD modulator count as chunk.size / SF_MOD_SIZE - 1 without rejecting chunks smaller than one record. A crafted SF2 file containing a zero-sized DMOD chunk makes the unsigned subtraction wrap to UINT_MAX, and the parser then attempts billions of SFMod allocations. This exhausts process memory and causes denial of service. No workaround is available. This issue is fixed in version 2.5.6.

Related CWEs

CWE-191

Integer Underflow (Wrap or Wraparound)

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

References (3)

https://github.com/FluidSynth/fluidsynth/commit/096e1ff0d09ddcac83d94923440706f76f94bc44

Source: security-advisories@github.com

https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.6

Source: security-advisories@github.com

https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-rmc4-c8hw-455w

Source: security-advisories@github.com

Timeline

No history available yet.