CVE-2026-111123Proof of concept (PoC) published · CISA

FluidSynth through 2.6.1 Out-of-Bounds Write via SoundFont Modulator Destination

CVSS score

6.9

EPSS probability

%0.2

Risk score

0.0

Published

3 d ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

Impact on My Inventory

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Vulnerability description

CVE AI research

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DayBreach AI Explanation

Verified against sources

FluidSynth through 2.6.1 Out-of-Bounds Write Vulnerability

Sources read

Source agreement

0/2

Evidence confidence

%44

Short explanation

FluidSynth through version 2.6.1 contains an out-of-bounds write vulnerability due to unvalidated SoundFont modulator destination values. This can lead to heap and stack memory corruption and crashes.

Why does it matter?

Loading and playing a crafted SF2 file can cause memory corruption and crashes, presenting a security risk.

What should be done?

Follow vendor advisories as the patch status cannot be reliably confirmed from official sources yet.

Note on uncertainty

2 alanda kaynak uyuşmazlığı var. DayBreach bu değerleri saklamadı; kaynak karşılaştırması aşağıda gösteriliyor.

Chain of evidence and sources2 verified claims

FluidSynth 2.6.1 ve öncesi, doğrulanmamış SoundFont modülatör hedef değerleri nedeniyle sınır dışı yazma zafiyeti barındırmaktadır.

S0 · daybreach-canonical S1 · cvelist S2 · nvd

Kötü amaçlı bir SF2 dosyası, ses üreteci dizisinin dışına yazarak bellek bozulmasına ve çökmelere neden olabilir.

S0 · daybreach-canonical S1 · cvelist S2 · nvd

Show the technical text from the sources

FluidSynth through 2.6.1 contains an out-of-bounds write vulnerability that allows attackers to corrupt heap and stack memory by supplying unvalidated SoundFont modulator destination values. Attackers can craft an SF2 file with PMOD/IMOD destinations of 63 to 255 that, when loaded and played, write past the voice generator array and updated_gen_bit, causing memory corruption and crashes.

CVSS vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N

CWE: CWE-787

Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-111123 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	FluidSynth	fluidsynth	View
2	debian	fluidsynth (sid)	View
3	debian	fluidsynth (forky)	View
4	debian	fluidsynth (trixie)	View
5	debian	fluidsynth (bookworm)	View

Total affected vendors: 2|Products: 5

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
6.9	CVSS V40	MEDIUM	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD
6.9	CVSS V4_0	MEDIUM	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N	CVE CNA
6.1	CVSS V31	MEDIUM	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H	NVD
6.1	CVSS V3_1	MEDIUM	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H	CVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-111123 is associated with the following CWEs:

CWE-787: Out-of-bounds Write

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-111123 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureYerel erişim

PermissionsGerekmiyor

User—

Official Sources and Advisories

https://hackmd.io/@haind-pwn/fluidsynth-sf2-modulator-dest-generator-oob-writevendor-advisory https://github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/src/synth/fluid_voice.c#L615-L623vendor-advisory https://github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/src/synth/fluid_voice.c#L1184-L1229vendor-advisory https://github.com/FluidSynth/fluidsynth/blob/71e85b2ca6bf48641ba7e2261d8f2640ae473773/src/sfloader/fluid_defsfont.c#L1609-L1611vendor-advisory https://github.com/FluidSynth/fluidsynthvendor-advisory VulnCheck Advisory: FluidSynth through 2.6.1 Out-of-Bounds Write via SoundFont Modulator Destinationvendor-advisory https://security-tracker.debian.org/tracker/CVE-2026-111123vendor-advisory

CVSS Vector Radar Chart

6.9 / 10

Vulnerability Scoring Details

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredNone required

User InteractionP

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)P

Availability (Erişilebilirlik)High

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

FluidSynth

debian

Weakness Type (CWE & CAPEC)

CWE-787

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