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CVE-2026-61720VulnerabilityPublished Updated

Fluidsynth: From 2.5.0 until 2.5.6, the SF2 parser computes the DMOD modulator count as chunk.size / SF_MOD_SIZE - 1

Affects fluidsynthSource GCVE Database

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Not known to be exploited · CVSS 6.2 Medium · fixed in 2.5.6 : update fluidsynth when convenient.

Data as of 7 Nov 2026, 23:24 UTC

CVSS 3.1 base score
6.2Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.5.6
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=resoluteOther threatsAffected
  • =2.4.7+dfsg-2
  • =2.4.8+dfsg-1
Fixed in–
Ubuntu Pro 26.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=esm-apps/resoluteOther threatsAffected
  • =2.4.7+dfsg-2
  • =2.4.8+dfsg-1
  • =2.4.8+dfsg-1ubuntu0.1~esm1
Fixed in–
Ubuntu 24.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=nobleOther threatsAffected
  • 2.3.3-2.1 – 2.3.4-1build3
5 affected builds
Fixed in–
Ubuntu Pro 24.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=esm-apps/nobleOther threatsAffected
  • 2.3.3-2.1 – 2.3.4-1ubuntu0.1~esm1
6 affected builds
Fixed in–
Ubuntu 22.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=jammyOther threatsAffected
  • =2.1.7-1.1
  • =2.2.4-2
  • =2.2.5-1
Fixed in–
Ubuntu Pro 22.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=esm-apps/jammyOther threatsAffected
  • 2.1.7-1.1 – 2.2.5-1ubuntu0.1~esm1
4 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

This vulnerability is fixed in FluidSynth version 2.5.6. Users should upgrade to version 2.5.6 or later to remediate this issue. No workaround or temporary fix is available.

Description

FluidSynth versions from 2.5.0 up to but not including 2.5.6 contain a vulnerability in the SF2 parser where a crafted SoundFont 2 (SF2) file with a zero-sized DMOD chunk causes an unsigned integer underflow. This results in the parser attempting to allocate an extremely large number of SFMod structures, exhausting process memory and causing a denial of service. The issue is fixed in version 2.5.6.

References

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