Fluidsynth: From 2.2.4 until 2.5.6, configuring synth.midi-channels above 16 allows the MIDI player to index
Affects fluidsynthSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 2.2.5-1ubuntu0.1~esm1 : patch fluidsynth soon.
Data as of 8 Nov 2026, 23:24 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.2.5-1ubuntu0.1~esm1, 2.3.4-1ubuntu0.1~esm1, 2.4.8+dfsg-1ubuntu0.1~esm1
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
Upgrade the Ubuntu fluidsynth to 2.2.5-1ubuntu0.1~esm1 (package) or 2.3.4-1ubuntu0.1~esm1 (package) or 2.4.8+dfsg-1ubuntu0.1~esm1 (package).
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu Pro 26.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=esm-apps/resoluteOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu Pro 24.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=esm-apps/nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTSfluidsynthpkg:deb/ubuntu/fluidsynth?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade FluidSynth to version 2.5.6 or later, where this vulnerability is fixed. Alternatively, keep the synth.midi-channels configuration at its default value of 16 to avoid triggering the vulnerable code path.
Description
FluidSynth versions from 2.2.4 up to but not including 2.5.6 have a vulnerability where configuring synth.midi-channels above 16 causes out-of-bounds memory access in the MIDI player. This occurs because the player indexes outside the fixed-size heap allocation for tracking active channels, leading to undefined behavior that can compromise confidentiality, integrity, and availability. The issue is triggered by configuration alone, without requiring a crafted MIDI file. The vulnerability is fixed in version 2.5.6.