CVE-2026-61720

medium

FluidSynth is a software synthesizer based on the SoundFont 2 specifications.

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.

CVSS

6.2

6.2 (CVSS v3.1)

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

Severity source: NVD CVSS v3.1 (security-advisories@github.com)

Timeline (UTC)

Published: 2026-09-18 20:17

Modified: 2026-09-24 21:25

NVD status: Deferred

Last synced 3 days ago

Verified against the source API 2026-10-27 06:54 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

Not reported by the source (unknown — not "none").

Weakness classification (CWE)

CWE-191

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

https://github.com/FluidSynth/fluidsynth/commit/096e1ff0d09ddcac83d94923440706f76f94bc44 security-advisories@github.com
https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.6 security-advisories@github.com
https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-rmc4-c8hw-455w security-advisories@github.com

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:54 UTC · record ↗

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