CVE-2025-68617Use after free in fluidsynth
- 7.0HighCVSS base score
- 0.21%Exploitation in 30 daysEPSS · top 88% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
Description
FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From versions 2.5.0 to before 2.5.2, a race condition during unloading of a DLS file can trigger a heap-based use-after-free. A concurrently running thread may be pending to unload a DLS file, leading to use of freed memory, if the synthesizer is being concurrently destroyed, or samples of the (unloaded) DLS file are concurrently used to synthesize audio. This issue has been patched in version 2.5.2. The problem will not occur, when explicitly unloading a DLS file (before synth destruction), provided that at the time of unloading, no samples of the respective file are used by active voices. The problem will not occur in versions of FluidSynth that have been compiled without native DLS support.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. 2 references of the record are tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits2
References tagged exploit2 references
- https://github.com/FluidSynth/fluidsynth/issues/1717 (opens in a new tab)x_refsource_MISCexploit
- https://github.com/FluidSynth/fluidsynth/issues/1728 (opens in a new tab)x_refsource_MISCexploit
Timeline
ID reserved
By GitHub_M
- 4 days later
· 4 days later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.0 | CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | High7.0 | CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.21% · top 88% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.0.
Affected products
- affected >= 2.5.0, < 2.5.2
References
References5
- https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-ffw2-xvvp-39ch (opens in a new tab)x_refsource_CONFIRM
- https://github.com/FluidSynth/fluidsynth/issues/1717 (opens in a new tab)x_refsource_MISCexploit
- https://github.com/FluidSynth/fluidsynth/issues/1728 (opens in a new tab)x_refsource_MISCexploit
- https://github.com/FluidSynth/fluidsynth/commit/685e54cdc44911ace31774260bd0c9ec89887491 (opens in a new tab)x_refsource_MISC
- https://github.com/FluidSynth/fluidsynth/commit/962b9946b5cb6b16f0c08b89dd1b7016d4fce886 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-205027 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-68617)Record last updated .