FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS parser validates articulation chunks using the unsigned expression cbsize + connblocks * 12 without first ensuring that the multiplication and addition fit in 32 bits. A crafted DLS file can supply a large connblocks value that wraps the expression and bypasses the chunk-size check, after which the parser performs approximately one billion 12-byte iterations beyond the chunk boundary. The excessive processing and invalid reads can cause denial of service. Builds with the CMake option enable-native-dls set to OFF do not expose the parser. This issue is fixed in version 2.5.6.
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History

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Description FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS parser validates articulation chunks using the unsigned expression cbsize + connblocks * 12 without first ensuring that the multiplication and addition fit in 32 bits. A crafted DLS file can supply a large connblocks value that wraps the expression and bypasses the chunk-size check, after which the parser performs approximately one billion 12-byte iterations beyond the chunk boundary. The excessive processing and invalid reads can cause denial of service. Builds with the CMake option enable-native-dls set to OFF do not expose the parser. This issue is fixed in version 2.5.6.
Title FluidSynth: DLS Articulation Chunk Integer Overflow
Weaknesses CWE-190
References
Metrics cvssV3_1

{'score': 6.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-18T20:01:58.603Z

Reserved: 2026-07-10T18:51:13.921Z

Link: CVE-2026-61722

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-18T20:17:18.713

Modified: 2026-09-18T20:17:18.713

Link: CVE-2026-61722

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses