Denial of service via DLS size-check overflow
Published Sep 18, 2026 · Updated Sep 18, 2026
Integer overflow in FluidSynth 2.5.0 through 2.5.5 allows local users to cause denial of service with a crafted DLS file. The native DLS parser computes cbsize + connblocks * 12 in 32-bit unsigned arithmetic, so a large connblocks value wraps and bypasses the articulation-chunk size check before roughly one billion out-of-bounds iterations. Exposure requires a build with enable-native-dls enabled and local processing of the crafted file; the resulting excessive work and invalid reads interrupt the process.
Summary
What happened
Integer overflow in FluidSynth 2.5.0 through 2.5.5 allows local users to cause denial of service with a crafted DLS file. The native DLS parser computes cbsize + connblocks * 12 in 32-bit unsigned arithmetic, so a large connblocks value wraps and bypasses the articulation-chunk size check before roughly one billion out-of-bounds iterations. Exposure requires a build with enable-native-dls enabled and local processing of the crafted file; the resulting excessive work and invalid reads interrupt the process.
The record
- CVE
- CVE-2026-61722
- Published
- Sep 18, 2026
- Updated
- Sep 18, 2026
- Vendor
- FluidSynth
- Product
- FluidSynth
- Classifications
- CWE-190
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 18, 2026CVE publishedPublication date reported by the CVE source.
- Sep 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 2.5.0, < 2.5.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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