FluidSynth is a software synthesizer based on the SoundFont 2 specifications. From 1.1.2 until 2.5.6, the FluidSynth command handler accepts a pitch_bend_range command whose channel argument is not bounds checked before the supplied value is written through the selected synth channel. An out-of-range channel can therefore cause an out-of-bounds heap write, leading to denial of service or possible code execution. The issue is remotely reachable when the TCP server is enabled through new_fluid_server() or fluidsynth -s, and it is locally reachable through malicious commands delivered to the FluidSynth shell on standard input. Applications that do not use the shell, command handler, or TCP server are not affected. This issue is fixed in version 2.5.6.
CVE-2026-58264
“—” beside the score: it is equal to the CVSS score beside it.
This critical-severity CVE scores 9.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6% (47th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
Also known asEUVD-2026-83374 (ENISA EUVD)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 9.8
- EG Score
- 9.8CRITICALmedium confidence
- EG Risk
- 59EG Risk 59/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity98% × 45%Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.6% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.6%
- EPSS %ILE
- 47th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
September 18, 2026
Last Modified
September 24, 2026
Advisory Details (4)
Auto-updated Oct 31, 2026Heap-based buffer overrun in command handler · Advisory · FluidSynth/fluidsynth · GitHub
https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-mqmq-w63q-cj94fluidsynth 2.5.6
Patch available: FluidSynth/fluidsynth v2.5.6
https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.6fix: add channel bounds check in pitch_bend_range to prevent OOB access
Upstream fix in progress (PR #1796 · FluidSynth/fluidsynth, state=closed)
https://github.com/FluidSynth/fluidsynth/pull/1796commit 762a3bd39a43 (FluidSynth/fluidsynth)
Patch available: FluidSynth/fluidsynth v2.5.6 (contains commit 762a3bd39a43)
https://github.com/FluidSynth/fluidsynth/commit/762a3bd39a431cd45abf3bbcce7286c87909d087Patch Availability(1)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libfluidsynth3 (2.4.8+dfsg-1ubuntu0.1~esm1) @ resolute | 2026-11-02 | ubuntu |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(3 across 3 ecosystems)
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| fluidsynth | 2.3.1-2 ... 2.6.0+dfsg-1 (33 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| fluidsynth | 2.4.4+dfsg-1, 2.4.4+dfsg-1+deb13u1, 2.4.4+dfsg-1+deb13u2 |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| fluidsynth | 2.4.4+dfsg-1 ... 2.5.5+dfsg-2 (13 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 20× in last 7d / 110× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 139 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 39 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-02 02:32 UTCEG score recompute
- 2026-11-02 02:32 UTCVendor advisory
- 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-11-01 03:13 UTCEG score recompute
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
- 2026-10-31 03:54 UTCEG score recompute
- 2026-10-31 03:54 UTCVendor advisory
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-30 04:34 UTCEG score recompute
- 2026-10-30 04:34 UTCVendor advisory
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-29 05:15 UTCEG score recompute
- 2026-10-29 05:15 UTCVendor advisory
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-28 05:56 UTCEG score recompute
- 2026-10-28 05:56 UTCVendor advisory
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-27 06:37 UTCEG score recompute
- 2026-10-27 06:37 UTCVendor advisory
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-26 03:35 UTCEG score recompute
- 2026-10-26 03:35 UTCVendor advisory
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-25 14:16 UTCEG score recompute
- 2026-10-25 04:15 UTCEG score recompute
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- 2026-10-25 04:15 UTCVendor advisory
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-24 04:57 UTCEG score recompute
- 2026-10-24 04:57 UTCVendor advisory
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-23 05:36 UTCEG score recompute
- 2026-10-23 05:36 UTCVendor advisory
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-22 06:16 UTCEG score recompute
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-21 06:54 UTCEG score recompute
- 2026-10-21 06:54 UTCVendor advisory
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
- 2026-10-20 07:35 UTCEG score recompute
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-19 08:15 UTCEG score recompute
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-18 08:55 UTCVendor advisory
- 2026-10-18 03:28 UTCEG score recompute
- 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-17 06:41 UTCEG score recompute
- 2026-10-17 06:41 UTCVendor advisory
- 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-16 07:20 UTCEG score recompute
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-15 06:14 UTCEG score recompute
- 2026-10-15 06:14 UTCVendor advisory
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-14 01:52 UTCEG score recompute
- 2026-10-14 01:52 UTCVendor advisory
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-12 22:07 UTCEG score recompute
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-12 15:53 UTCEG score recompute
- 2026-10-12 04:49 UTCVendor advisory
- 2026-10-11 23:03 UTCVendor advisory
- 2026-10-11 19:12 UTCEG score recompute
- 2026-10-11 19:12 UTCVendor advisory
- 2026-10-11 16:52 UTCEG score recompute
- 2026-10-11 15:21 UTCVendor advisory
- 2026-10-11 14:14 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-11 11:29 UTCEG score recompute
- 2026-10-11 11:29 UTCVendor advisory
- 2026-10-11 07:36 UTCVendor advisory
- 2026-10-11 03:39 UTCVendor advisory
- 2026-10-10 23:45 UTCEG score recompute
- 2026-10-10 23:45 UTCVendor advisory
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-10 19:54 UTCVendor advisory
- 2026-10-10 16:00 UTCVendor advisory
- 2026-10-10 12:09 UTCVendor advisory
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- 2026-10-10 04:26 UTCVendor advisory
- 2026-10-10 00:35 UTCVendor advisory
- 2026-10-09 20:44 UTCEG score recompute
- 2026-10-09 20:44 UTCVendor advisory
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-09 16:52 UTCVendor advisory
- 2026-10-09 12:56 UTCVendor advisory
- 2026-10-09 08:57 UTCVendor advisory
- 2026-10-09 04:57 UTCVendor advisory
- 2026-10-09 01:06 UTCVendor advisory
- 2026-10-08 21:14 UTCVendor advisory
- 2026-10-08 17:24 UTCEG score recompute
- 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 46th percentile
- 2026-10-08 09:31 UTCVendor advisory
- 2026-10-08 05:40 UTCVendor advisory
- 2026-10-08 01:48 UTCEG score recompute
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 55th percentile
- 2026-10-07 21:57 UTCVendor advisory
- 2026-10-07 12:48 UTCVendor advisory
- 2026-10-07 08:35 UTCVendor advisory
- 2026-10-07 04:44 UTCVendor advisory
- 2026-10-07 00:53 UTCVendor advisory
Related CVEs(same product + same vendor + same CWE)
Same product
8 shownDebian:12:fluidsynth · Debian:14:fluidsynth
Frequently asked(5)
What is CVE-2026-58264?
When was the CVE record for CVE-2026-58264 published?
Is CVE-2026-58264 actively exploited?
What is the CVSS score of CVE-2026-58264?
How do I remediate CVE-2026-58264?
Dependency Blast Radius
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