Fluidsynth: From 2.5.0 until 2.5.6, the native DLS parser validates ptbl chunks with the unsigned expression cues 4 +
Affects fluidsynthSource GCVE Database
Not known to be exploited · CVSS 6.8 Medium · fixed in 2.5.6 : update fluidsynth when convenient.
Data as of 8 Nov 2026, 23:24 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% 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:L/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
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, use builds with native DLS parsing disabled (enable-native-dls set to OFF), which are not exposed to this issue. No other mitigation is indicated by the vendor advisory.
Description
FluidSynth versions from 2.5.0 up to but not including 2.5.6 contain a vulnerability in the native DLS parser. The parser improperly validates ptbl chunks by using an unsigned expression that can overflow 32 bits, leading to excessive memory allocation and out-of-bounds reads. This can cause a denial of service. The issue is fixed in version 2.5.6. Builds with native DLS parsing disabled are not affected.