TI-2026-44176 Aliases CVE-2026-61714

FluidSynth: Heap Buffer Overflow in MIDI Player

LOW 35CWE-122Published 2026-09-18 · Updated 2026-09-25

Key facts

Attack vector: Local
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Code execution
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-122 and the CVSS impact.

Summary

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.2.4 until 2.5.6, configuring synth.midi-channels above 16 allows the MIDI player to index _fluid_player_t::channel_isplaying outside its fixed-size heap allocation while tracking active channels. The resulting out-of-bounds reads and writes invoke undefined behavior and may compromise confidentiality, integrity, or availability. No crafted MIDI file is required because the unsafe condition is created by the channel-count configuration itself. Keeping synth.midi-channels at its default value of 16 avoids the vulnerable path. This issue is fixed in version 2.5.6.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00143 3rd percentileScored 2026-11-07

Fix Fixed fluidsynth (FluidSynth): 2.5.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
FluidSynth	fluidsynth	2.2.4 to before 2.5.6	2.5.6	Patch available	CNA

fluidsynth VendorFluidSynth Affected 2.2.4 to before 2.5.6 Fixed in 2.5.6 Patch available CNA

Remediation

Fix · CNA fluidsynth (FluidSynth) Fixed in 2.5.6

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product

Red Hat

Timeline

2026-10-02 Threatist record created from CVE-2026-61714

References

Other 3

TI-2025-35279 fluidsynth-2.4.6 and earlier versions is vulnerable to Null pointer dereference in… CVSS 3.1HIGH 7.5
TI-2025-42135 Use after free in fluidsynth CVSS 3.1HIGH 7.0
TI-2026-74907 Out-of-bounds write in FluidSynth SoundFont modulator handling CVSS 4.0MEDIUM 6.9
TI-2026-41957 FluidSynth: Heap-based buffer overrun CVSS 3.1CRITICAL 9.8
TI-2026-44179 FluidSynth: Heap-based buffer overrun for DLS samples CVSS 3.1HIGH 8.0
TI-2021-04515 Use after free in fluidsynth CVSS 3.1HIGH 7.2

See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences