# CVE-2026-61714: FluidSynth: Heap Buffer Overflow in MIDI Player

> Heap buffer overflow in FluidSynth MIDI player allows code execution or denial of service when synth.midi-channels is configured above 16.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **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 available:** Yes
- **Published:** 18 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-61714, ECHO-586f-1d4c-181d, GHSA-976m-35rw-h3m6, OESA-2026-3165, OESA-2026-3166, OESA-2026-3168, UBUNTU-CVE-2026-61714

## What is CVE-2026-61714?

CVE-2026-61714 is a high-severity memory corruption vulnerability in fluidsynth, published on 18 Sep 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 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.

Weakness: CWE-787 (Out-of-bounds Write), CWE-125 (Out-of-bounds Read), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-61714?


## How do I fix CVE-2026-61714?

Upgrade to a fixed version.

## Is CVE-2026-61714 being exploited?

There is no known exploitation of CVE-2026-61714 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61714 and fix it if it is affected.

What it is: CVE-2026-61714 is a high-severity memory corruption vulnerability in fluidsynth, published on 18 Sep 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.
Exploitation: There is no known exploitation of CVE-2026-61714 in the wild and no public exploit code.

Affected product: fluidsynth. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-61714/ (Markdown: https://insights.sbomify.com/CVE-2026-61714/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61714
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61714
- OSV: https://osv.dev/vulnerability/CVE-2026-61714

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61714/
Summaries are generated and may contain mistakes; the official description above is the record.