CVE-2026-111123 FluidSynth through 2.6.1 Out-of-Bounds Write via SoundFont Modulator Destination
Attackers can execute arbitrary code or cause denial of service by supplying a malicious SoundFont file to FluidSynth.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-111123?
CVE-2026-111123 is a medium-severity memory corruption vulnerability in fluidsynth, published on 15 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-787
Which versions are affected by CVE-2026-111123?
How do I fix CVE-2026-111123?
No fix has been published for CVE-2026-111123 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-111123 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111123 exists.
Sources
Also known as DEBIAN-CVE-2026-111123, ECHO-9bbe-0684-519c, GHSA-7hc9-ggv2-4w8c, UBUNTU-CVE-2026-111123.