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Fencer Vulns
high 7.8

CVE-2026-61714 json

FluidSynth: Heap Buffer Overflow in MIDI Player

published 2026-09-18 51 d ago modified 2026-09-25 44 d ago also EUVD-2026-83376

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 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

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
44 d ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 Vulns 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.