CVE-2026-61722

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.

Database specific

{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-190"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/61xxx/CVE-2026-61722.json"
}

References

Affected packages

Git / github.com/fluidsynth/fluidsynth

Affected ranges

Type

GIT

Repo

https://github.com/fluidsynth/fluidsynth

Events

Introduced

df432e151dcaf463b1ecc7e873803bfa19733fd3

Fixed

e5b11058a619246cea42976dacb76ca54be3d45d

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "2.5.0"
        },
        {
            "fixed": "2.5.6"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Affected versions

v2.*

v2.5.0

v2.5.1

v2.5.2

v2.5.3

v2.5.4

v2.5.5

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-61722.json"

vanir_signatures

[
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "65741976735742723877597808461499147360",
                "158873129713208397340236107564649355567",
                "27858880504209789441457038429492907366",
                "242142550883552540884961556422285883183"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-61722-ae4f73c0",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/fluidsynth/fluidsynth/commit/e5b11058a619246cea42976dacb76ca54be3d45d",
        "target": {
            "file": "src/sfloader/fluid_dls.cpp"
        }
    },
    {
        "deprecated": false,
        "digest": {
            "function_hash": "109398306651516327573478367773148522902",
            "length": 9029
        },
        "id": "CVE-2026-61722-b1a5b579",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/fluidsynth/fluidsynth/commit/e5b11058a619246cea42976dacb76ca54be3d45d",
        "target": {
            "file": "src/sfloader/fluid_dls.cpp",
            "function": "fluid_dls_font::fluid_dls_font"
        }
    }
]

vanir_signatures_modified

"2026-09-19T14:02:31Z"