CVE-2026-61720

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Source
https://cve.org/CVERecord?id=CVE-2026-61720
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-61720.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-61720
Aliases
  • GHSA-rmc4-c8hw-455w
Downstream
Published
2026-09-18T20:03:43Z
Modified
2026-09-19T14:02:32Z
Severity
  • 6.2 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
FluidSynth: SF2 DMOD Chunk Unsigned Underflow
Details

FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the SF2 parser computes the DMOD modulator count as chunk.size / SF_MOD_SIZE - 1 without rejecting chunks smaller than one record. A crafted SF2 file containing a zero-sized DMOD chunk makes the unsigned subtraction wrap to UINT_MAX, and the parser then attempts billions of SFMod allocations. This exhausts process memory and causes denial of service. No workaround is available. This issue is fixed in version 2.5.6.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-191"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/61xxx/CVE-2026-61720.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-2026-61720.json"
vanir_signatures 
[
    {
        "deprecated": false,
        "digest": {
            "line_hashes": [
                "65741976735742723877597808461499147360",
                "158873129713208397340236107564649355567",
                "27858880504209789441457038429492907366",
                "242142550883552540884961556422285883183"
            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-61720-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-2026-61720-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 
"2026-09-19T14:02:32Z"