CVE-2026-61723 FluidSynth: DLS ptbl Chunk Integer Overflow
A crafted DLS file triggers an integer overflow in FluidSynth's native parser, causing excessive memory allocation and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61723?
CVE-2026-61723 is a medium-severity vulnerability in fluidsynth, published on 18 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS parser validates ptbl chunks with the unsigned expression cues * 4 + cbsize without checking whether the multiplication and addition fit in 32 bits. A crafted DLS file can supply a large cues value that wraps the expression and passes the chunk-size check, causing poolcues.resize(cues) to request approximately four gigabytes and the parser to read billions of entries beyond the chunk boundary. The excessive allocation and invalid reads can cause denial of service. Builds with enable-native-dls set to OFF are not exposed. This issue is fixed in version 2.5.6.
Weakness: CWE-190
Which versions are affected by CVE-2026-61723?
How do I fix CVE-2026-61723?
Upgrade to a fixed version.
Is CVE-2026-61723 being exploited?
There is no known exploitation of CVE-2026-61723 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-61723, GHSA-r4mc-v3p8-pv47, UBUNTU-CVE-2026-61723.