← CVE Intelligence

CVE-2026-61720

FluidSynth: SF2 DMOD Chunk Unsigned Underflow PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
FluidSynth / fluidsynthaffected >= 2.5.0, < 2.5.6

CWE

CWE-191

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.