FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS loader assigns file-controlled wsmp.loop_start and wsmp.loop_length values to samples without calling fluid_sample_validate() or fluid_sample_sanitize_loop(). A crafted DLS file can place sample loop points beyond the sample buffer, causing out-of-bounds reads during audio rendering, undefined behavior, possible memory disclosure, and denial of service. Builds compiled with the CMake option enable-native-dls set to OFF do not expose the affected parser. This issue is fixed in version 2.5.6.
CVE-2026-61721
HIGHPre-NVD 8.08.0—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 96% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
8.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.0Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.0
- EG Score
- 8.0(medium)
- EG Risk
- 41(Track)EG Risk 41/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity80% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 4%
- KEV
- Not listed
Published
September 18, 2026
Last Modified
September 18, 2026
Advisory Details (3)
Auto-updated Sep 18, 2026Patch available. Sources: github, github_commit, github_release.
github_release Patch Available
fluidsynth 2.5.6
Patch available: FluidSynth/fluidsynth v2.5.6
https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.6github_commit Patch Available
commit 2354c2a9acdb (FluidSynth/fluidsynth)
Patch available: FluidSynth/fluidsynth v2.5.6 (contains commit 2354c2a9acdb)
https://github.com/FluidSynth/fluidsynth/commit/2354c2a9acdb26de7cdcd37c903ee108f46c0a7dgithub Patch Available
Heap-based buffer overrun for DLS samples · Advisory · FluidSynth/fluidsynth · GitHub
https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-59ph-rx8r-8p4jWeakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-09-20 23:34 UTCEG score recompute
- 2026-09-20 20:16 UTCEPSS rescore
- 2026-09-19 22:25 UTCEG score recompute
- 2026-09-18 20:30 UTCEG score recompute
- 2026-09-18 20:10 UTCEG score recompute
- 2026-09-18 20:09 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-122
Frequently asked(5)
What is CVE-2026-61721?
CVE-2026-61721 is a high vulnerability published on September 18, 2026. FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS loader assigns file-controlled wsmp.loopstart and wsmp.looplength values to samples without calling fluidsamplevalidate() or fluidsamplesanitize_loop(). A crafted DLS file can place…
When was CVE-2026-61721 disclosed?
CVE-2026-61721 was first published in the National Vulnerability Database on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-61721 actively exploited?
CVE-2026-61721 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 95.5% of all scored CVEs.
What is the CVSS score of CVE-2026-61721?
CVE-2026-61721 has a CVSS v3 base score of 8.0 (NVD).
How do I remediate CVE-2026-61721?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-61721, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-61721
Is Your Infrastructure Affected by CVE-2026-61721?
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