CVE-2021-21417

Name: CVE-2021-21417
Creator: NVD / NIST
Published: 2021-04-29T17:15:09.023+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.94%

Last modified Jun 17, 2026

CVE-2021-21417 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. fluidsynth is a software synthesizer based on the SoundFont 2 specifications. A use after free violation was discovered in fluidsynth, that can be triggered when loading an invalid SoundFont file.. EPSS estimates a 0.94% chance of exploitation in the next 30 days.

Description

fluidsynth is a software synthesizer based on the SoundFont 2 specifications. A use after free violation was discovered in fluidsynth, that can be triggered when loading an invalid SoundFont file.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability

0.94%

56.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Fluidsynth	Fluidsynth	< 2.1.8
Debian	Debian Linux	9.0

References

https://github.com/FluidSynth/fluidsynth/issues/808Exploit, Third Party Advisory
https://github.com/FluidSynth/fluidsynth/pull/810Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-6fcq-pxhc-jxc9Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00027.htmlMailing List, Third Party Advisory
https://github.com/FluidSynth/fluidsynth/issues/808Exploit, Third Party Advisory
https://github.com/FluidSynth/fluidsynth/pull/810Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-6fcq-pxhc-jxc9Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00027.htmlMailing List, Third Party Advisory

Timeline

Published: Apr 29, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21417?

fluidsynth is a software synthesizer based on the SoundFont 2 specifications. A use after free violation was discovered in fluidsynth, that can be triggered when loading an invalid SoundFont file.

How severe is CVE-2021-21417?

CVE-2021-21417 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.94% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21417?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21417?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST