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Fencer Intel
high 8.0

CVE-2026-61721 json

FluidSynth: Heap-based buffer overrun for DLS samples

published 4mo ago modified last mo. also EUVD-2026-83375 , GHSA-59ph-rx8r-8p4j

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
8.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS loader assigns file-controlled wsmp.loop_start and wsmp.loop_length values to samples without calling fluid_sample_validate() or fluid_sample_sanitize_loop(). A crafted DLS file can place sample loop points beyond the sample buffer, causing out-of-bounds reads during audio rendering, undefined behavior, possible memory disclosure, and denial of service. Builds compiled with the CMake option enable-native-dls set to OFF do not expose the affected parser. This issue is fixed in version 2.5.6.

Patch / fix

  • fluidsynth fluidsynth 2.5.6
  • fluidsynth Debian 14 2.5.6+dfsg-1

debian advisories DEBIAN-CVE-2026-61721

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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-2026-61721 updated cvss 8.0

FluidSynth: FluidSynth: Memory Disclosure and Denial of Service via Crafted DLS File

  • 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
partial
Assessed
last mo.

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 8.0 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:L/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.