Vulnerability in FluidSynth (CVE-2026-61723)
Summary
Vulnerability in FluidSynth (CVE-2026-61723). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 2.5.0 until 2.5.6, the native DLS parser validates ptbl chunks with the unsigned expression cues * 4 + cbsize without checking whether the multiplication and addition fit in 32 bits. A crafted DLS file can supply a large cues value that wraps the expression and passes the chunk-size check, causing poolcues.resize(cues) to request approximately four gigabytes and the parser to read billions of entries beyond the chunk boundary. The excessive allocation and invalid reads can cause denial of service. Builds with enable-native-dls set to OFF are not exposed. This issue is fixed in version 2.5.6.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-61723 has been found in FluidSynth.
Risk of unauthorized operations or information disclosure. CVSS score: 6.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "FluidSynth CVE-2026-61723" on the vendor's site.
CVE-2026-61723 (FluidSynth) — CWE-190 / CVSS v3 6.8
Attack vector: local / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-190) exists in FluidSynth.
Check the vendor advisory for the affected versions of FluidSynth.
Severity: Medium (CVSS 6.8/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'FluidSynth' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'FluidSynth' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
FluidSynthを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。