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CVE-2021-21417

Use after free in fluidsynth

7.2 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
High
Privileges needed
Low
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
None

Exploit likelihood

0.94%Up 0.3 points since Apr 30, 2021
90%50%10%1%

What each source reports

CVE List Score used 7.2

Use after free in fluidsynth

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.

Record
CVE-2021-21417
CVSS 3.1
7.2 HighCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
Weakness
CWE-416
Updated
2026-11-02
EUVDEUVD-2021-8704 7.2

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.

Record
EUVD-2021-8704
CVSS 3.1
7.2 HighCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
Updated
2026-11-03
NVD 7.2

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.

Record
CVE-2021-21417
CVSS 3.1
7.2 HighCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.0
4.3 MediumAV:N/AC:M/Au:N/C:N/I:N/A:P
Weakness
CWE-416
Updated
2026-11-02
OSVALPINE-CVE-2021-21417 5.5

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.

Record
ALPINE-CVE-2021-21417
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-03
OSV 5.5

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.

Record
CVE-2021-21417
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-21417 5.5

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.

Record
DEBIAN-CVE-2021-21417
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2021-21417 7.2

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.

Record
UBUNTU-CVE-2021-21417
CVSS 3.1
7.2 HighCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVMGASA-2021-0324 No score

Updated fluidsynth packages fix a security vulnerability

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 (CVE-2021-21417).

Record
MGASA-2021-0324
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
fluidsynth
Alpine:v3.13
 before 2.1.8-r0
2.1.8-r0
fluidsynth
Debian:12
 before 2.1.7-1.1
2.1.7-1.1
fluidsynth
Debian:13
 before 2.1.7-1.1
2.1.7-1.1
fluidsynth
Debian:14
 before 2.1.7-1.1
2.1.7-1.1
fluidsynth
Debian:9
 before 1.1.6-4+deb9u1, plus listed versions
1.1.6-4
1.1.6-4+deb9u1
fluidsynth
Mageia:7
 before 2.0.5-1.1.mga7
2.0.5-1.1.mga7
fluidsynth
Mageia:8
 before 2.1.8-1.mga8
2.1.8-1.mga8
fluidsynth
Ubuntu:Pro:14.04:LTS
 All versions, plus listed versions
1.1.6-21.1.6-2ubuntu0.1~esm1
 None known
fluidsynth
Ubuntu:Pro:16.04:LTS
 All versions, plus listed versions
1.1.6-2build11.1.6-31.1.6-3ubuntu0.1~esm1
 None known
fluidsynth
Ubuntu:Pro:18.04:LTS
 All versions, plus listed versions
1.1.6-41.1.8-11.1.8-21.1.8-31.1.9-11.1.9-1ubuntu0.1~esm1
 None known
fluidsynth
Ubuntu:Pro:20.04:LTS
 All versions, plus listed versions
1.1.11-41.1.11-4ubuntu12.1.0-12.1.1-22.1.1-2ubuntu0.1~esm1
 None known
fluidsynth
Ubuntu:Pro:22.04:LTS
 All versions, plus listed versions
2.1.7-1.12.2.4-22.2.5-12.2.5-1ubuntu0.1~esm1
 None known

History

History
RecordedChangedSources
affected, aliases, referencesOSV
aliasesEUVD
first indexedCVE List, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-21417 is a high vulnerability (CVSS 7.2) in Fluidsynth, published April 29, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.94%, the 61st percentile. Fixed in fluidsynth 2.1.8-r0.

References

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