{"id":"CVE-2026-61720","title":"FluidSynth is a software synthesizer based on the SoundFont 2 specifications","summary":"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 cr…","severity":"medium","cvss":6.2,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-191"],"vendor":"FluidSynth","product":"fluidsynth","affected":["fluidsynth >= 2.5.0, < 2.5.6"],"published":"2026-09-18","updated":"2026-09-21","sourceUpdated":"2026-09-21T17:17:36.827","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-61720","references":[{"url":"https://github.com/FluidSynth/fluidsynth/commit/096e1ff0d09ddcac83d94923440706f76f94bc44","label":"security-advisories@github.com"},{"url":"https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.6","label":"security-advisories@github.com"},{"url":"https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-rmc4-c8hw-455w","label":"security-advisories@github.com"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-21T16:27:05.665077Z"},"epss":0.00143,"epssPercentile":0.03941,"ingestedAt":"2026-09-18T20:51:25.675Z","slug":"CVE-2026-61720","body":"## Overview\n\nFluidSynth 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":34,"depthScoreParts":{"impact":34.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}