Buffer overflow in Fluidsynth
CVE-2026-111123
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- hackmd.io/@haind-pwn/fluidsynth-sf2-modulator-dest-generator-oob-write (technical-description)
- github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/… (technical-description)
- github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/… (technical-description)
- github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/… (technical-description)
- github.com/FluidSynth/fluidsynth (product)
- www.vulncheck.com/advisories/fluidsynth-through-2.6.1-out-of-bounds-write-via-s… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-111123?
- CVE-2026-111123 is a medium-severity vulnerability in Fluidsynth, classified under Out-of-bounds Write. CVSS score: 6.1/10. Published 2026-10-15.
- How severe is CVE-2026-111123?
- Medium severity. CVSS v3 base score is 6.1 out of 10.