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TI-2026-41957 Aliases CVE-2026-58264

FluidSynth: Heap-based buffer overrun

Priority MEDIUM 50CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-122 and the CVSS impact.

Summary

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 1.1.2 until 2.5.6, the FluidSynth command handler accepts a pitch_bend_range command whose channel argument is not bounds checked before the supplied value is written through the selected synth channel. An out-of-range channel can therefore cause an out-of-bounds heap write, leading to denial of service or possible code execution. The issue is remotely reachable when the TCP server is enabled through new_fluid_server() or fluidsynth -s, and it is locally reachable through malicious commands delivered to the FluidSynth shell on standard input. Applications that do not use the shell, command handler, or TCP server are not affected. This issue is fixed in version 2.5.6.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00586 48th percentileScored 2026-11-07
Fix Fixed fluidsynth (FluidSynth): 2.5.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FluidSynthfluidsynth1.1.2 to before 2.5.62.5.6Patch availableCNA
  • fluidsynth VendorFluidSynth Affected 1.1.2 to before 2.5.6 Fixed in 2.5.6 Patch available CNA

Remediation

  • Fix · CNA fluidsynth (FluidSynth) Fixed in 2.5.6

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-58264
  2. 2026-10-08 EPSS moved to the below the 50th percentile
  3. 2026-10-08 Affected versions changed · Red Hat
  4. 2026-10-08 CVSS score added · Red Hat

References

Other 4

  • TI-2025-35279 fluidsynth-2.4.6 and earlier versions is vulnerable to Null pointer dereference in… CVSS 3.1HIGH 7.5
  • TI-2025-42135 Use after free in fluidsynth CVSS 3.1HIGH 7.0
  • TI-2026-74907 Out-of-bounds write in FluidSynth SoundFont modulator handling CVSS 4.0MEDIUM 6.9
  • TI-2026-44176 FluidSynth: Heap Buffer Overflow in MIDI Player CVSS 3.1HIGH 7.8
  • TI-2026-44179 FluidSynth: Heap-based buffer overrun for DLS samples CVSS 3.1HIGH 8.0
  • TI-2021-04515 Use after free in fluidsynth CVSS 3.1HIGH 7.2
See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences