Description
FluidSynth through 2.6.1 contains an out-of-bounds write vulnerability that allows attackers to corrupt heap and stack memory by supplying unvalidated SoundFont modulator destination values. Attackers can craft an SF2 file with PMOD/IMOD destinations of 63 to 255 that, when loaded and played, write past the voice generator array and updated_gen_bit, causing memory corruption and crashes.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| FluidSynth | fluidsynth | ≤ 2.6.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | fluidsynth | No fix yet | — |
| Debian 13 | fluidsynth | No fix yet | — |
| Debian 12 | fluidsynth | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | fluidsynth | No fix yet | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | fluidsynth | No fix yet | — |
| Ubuntu Pro 24.04 LTS | fluidsynth | No fix yet | — |
| Ubuntu Pro 22.04 LTS | fluidsynth | No fix yet | — |
| Ubuntu Pro 20.04 LTS | fluidsynth | No fix yet | — |
| Ubuntu Pro 18.04 LTS | fluidsynth | No fix yet | — |
| Ubuntu Pro 16.04 LTS | fluidsynth | No fix yet | — |
| Ubuntu Pro 14.04 LTS | fluidsynth | No fix yet | — |
References
- https://hackmd.io/@haind-pwn/fluidsynth-sf2-modulator-dest-generator-oob-write technical-description
- https://github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/src/synth/fluid_voice.c#L615-L623 technical-description
- https://github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/src/synth/fluid_voice.c#L1184-L1229 technical-description
- https://github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/src/sfloader/fluid_defsfont.c#L1609-L1611 technical-description
- https://github.com/FluidSynth/fluidsynth product
- VulnCheck Advisory: FluidSynth through 2.6.1 Out-of-Bounds Write via SoundFont Modulator Destination third-party-advisory