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Fencer Intel
high 7.8

CVE-2026-61714 json

FluidSynth: Heap Buffer Overflow in MIDI Player

published 4mo ago modified last mo. also EUVD-2026-83376 , GHSA-976m-35rw-h3m6

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository FluidSynth/fluidsynth. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

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.

Patch / fix

  • fluidsynth fluidsynth 2.5.6
  • fluidsynth Debian 13 2.4.4+dfsg-1+deb13u3
  • fluidsynth Debian 14 2.5.6+dfsg-1

debian advisories DEBIAN-CVE-2026-61714

  • fluidsynth Ubuntu Pro 22.04 LTS 2.2.5-1ubuntu0.1~esm1
  • fluidsynth Ubuntu Pro 24.04 LTS 2.3.4-1ubuntu0.1~esm1
  • fluidsynth Ubuntu Pro 26.04 LTS 2.4.8+dfsg-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2026-61714

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-61714 updated cvss 7.8

FluidSynth: FluidSynth: Heap Buffer Overflow via MIDI channel configuration

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
last mo.

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • FluidSynth fluidsynth

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of FluidSynth/fluidsynth published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.