CVE-2026-58264

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

“—” 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.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-83374 (ENISA EUVD)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
59
EG 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, 2026
Patch available. Sources: github_commit, github_pr, github_release, github.
GitHub advisoryMentions a patch (unverified)

Heap-based buffer overrun in command handler · Advisory · FluidSynth/fluidsynth · GitHub

https://github.com/FluidSynth/fluidsynth/security/advisories/GHSA-mqmq-w63q-cj94
GitHub release Patch Available

fluidsynth 2.5.6

Patch available: FluidSynth/fluidsynth v2.5.6

https://github.com/FluidSynth/fluidsynth/releases/tag/v2.5.6
GitHub pull request

fix: 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/1796
GitHub commit Patch Available

commit 762a3bd39a43 (FluidSynth/fluidsynth)

Patch available: FluidSynth/fluidsynth v2.5.6 (contains commit 762a3bd39a43)

https://github.com/FluidSynth/fluidsynth/commit/762a3bd39a431cd45abf3bbcce7286c87909d087

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibfluidsynth3 (2.4.8+dfsg-1ubuntu0.1~esm1) @ resolute2026-11-02ubuntu

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)
PackageVulnerable rangeFix by version rangeDependents
fluidsynth2.3.1-2 ... 2.6.0+dfsg-1 (33 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
fluidsynth2.4.4+dfsg-1, 2.4.4+dfsg-1+deb13u1, 2.4.4+dfsg-1+deb13u2
  • every version up to 2.4.4+dfsg-1+deb13u3: fixed in 2.4.4+dfsg-1+deb13u3
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
fluidsynth2.4.4+dfsg-1 ... 2.5.5+dfsg-2 (13 versions)
  • every version up to 2.5.6+dfsg-1: fixed in 2.5.6+dfsg-1
—

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.

  1. 2026-11-02 02:32 UTCEG score recompute
  2. 2026-11-02 02:32 UTCVendor advisory
  3. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  4. 2026-11-01 03:13 UTCEG score recompute
  5. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  6. 2026-10-31 03:54 UTCEG score recompute
  7. 2026-10-31 03:54 UTCVendor advisory
  8. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  9. 2026-10-30 04:34 UTCEG score recompute
  10. 2026-10-30 04:34 UTCVendor advisory
  11. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  12. 2026-10-29 05:15 UTCEG score recompute
  13. 2026-10-29 05:15 UTCVendor advisory
  14. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  15. 2026-10-28 05:56 UTCEG score recompute
  16. 2026-10-28 05:56 UTCVendor advisory
  17. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  18. 2026-10-27 06:37 UTCEG score recompute
  19. 2026-10-27 06:37 UTCVendor advisory
  20. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  21. 2026-10-26 03:35 UTCEG score recompute
  22. 2026-10-26 03:35 UTCVendor advisory
  23. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  24. 2026-10-25 14:16 UTCEG score recompute
  25. 2026-10-25 04:15 UTCEG score recompute
Show 75 more
  1. 2026-10-25 04:15 UTCVendor advisory
  2. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  3. 2026-10-24 04:57 UTCEG score recompute
  4. 2026-10-24 04:57 UTCVendor advisory
  5. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  6. 2026-10-23 05:36 UTCEG score recompute
  7. 2026-10-23 05:36 UTCVendor advisory
  8. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  9. 2026-10-22 06:16 UTCEG score recompute
  10. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  11. 2026-10-21 06:54 UTCEG score recompute
  12. 2026-10-21 06:54 UTCVendor advisory
  13. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  14. 2026-10-20 07:35 UTCEG score recompute
  15. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  16. 2026-10-19 08:15 UTCEG score recompute
  17. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  18. 2026-10-18 08:55 UTCVendor advisory
  19. 2026-10-18 03:28 UTCEG score recompute
  20. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-10-17 06:41 UTCEG score recompute
  22. 2026-10-17 06:41 UTCVendor advisory
  23. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-10-16 07:20 UTCEG score recompute
  25. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  26. 2026-10-15 06:14 UTCEG score recompute
  27. 2026-10-15 06:14 UTCVendor advisory
  28. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  29. 2026-10-14 01:52 UTCEG score recompute
  30. 2026-10-14 01:52 UTCVendor advisory
  31. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  32. 2026-10-12 22:07 UTCEG score recompute
  33. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  34. 2026-10-12 15:53 UTCEG score recompute
  35. 2026-10-12 04:49 UTCVendor advisory
  36. 2026-10-11 23:03 UTCVendor advisory
  37. 2026-10-11 19:12 UTCEG score recompute
  38. 2026-10-11 19:12 UTCVendor advisory
  39. 2026-10-11 16:52 UTCEG score recompute
  40. 2026-10-11 15:21 UTCVendor advisory
  41. 2026-10-11 14:14 UTCEG score recompute
  42. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-10-11 11:29 UTCEG score recompute
  44. 2026-10-11 11:29 UTCVendor advisory
  45. 2026-10-11 07:36 UTCVendor advisory
  46. 2026-10-11 03:39 UTCVendor advisory
  47. 2026-10-10 23:45 UTCEG score recompute
  48. 2026-10-10 23:45 UTCVendor advisory
  49. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  50. 2026-10-10 19:54 UTCVendor advisory
  51. 2026-10-10 16:00 UTCVendor advisory
  52. 2026-10-10 12:09 UTCVendor advisory
  53. 2026-10-10 08:17 UTCVendor advisory
  54. 2026-10-10 04:26 UTCVendor advisory
  55. 2026-10-10 00:35 UTCVendor advisory
  56. 2026-10-09 20:44 UTCEG score recompute
  57. 2026-10-09 20:44 UTCVendor advisory
  58. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  59. 2026-10-09 16:52 UTCVendor advisory
  60. 2026-10-09 12:56 UTCVendor advisory
  61. 2026-10-09 08:57 UTCVendor advisory
  62. 2026-10-09 04:57 UTCVendor advisory
  63. 2026-10-09 01:06 UTCVendor advisory
  64. 2026-10-08 21:14 UTCVendor advisory
  65. 2026-10-08 17:24 UTCEG score recompute
  66. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  67. 2026-10-08 09:31 UTCVendor advisory
  68. 2026-10-08 05:40 UTCVendor advisory
  69. 2026-10-08 01:48 UTCEG score recompute
  70. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.8% · 55th percentile
  71. 2026-10-07 21:57 UTCVendor advisory
  72. 2026-10-07 12:48 UTCVendor advisory
  73. 2026-10-07 08:35 UTCVendor advisory
  74. 2026-10-07 04:44 UTCVendor advisory
  75. 2026-10-07 00:53 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-58264?
CVE-2026-58264 is a critical-severity vulnerability; its CVE record was published on September 18, 2026. 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…
When was the CVE record for CVE-2026-58264 published?
The CVE record for CVE-2026-58264 was published on September 18, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 24, 2026; the record at its source may have been updated since.
Is CVE-2026-58264 actively exploited?
CVE-2026-58264 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (47th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-58264?
CVE-2026-58264 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-58264?
A fix for CVE-2026-58264 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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