# CVE-2026-116731: Furnace through 0.6.8.3 Out-of-Bounds Write via FamiTracker GROOVES Block Import

Status: published. Published: 2026-10-26. Updated: 2026-11-05.

Furnace through 0.6.8.3 contains an out-of-bounds write vulnerability in DivEngine::loadFTM() that allows attackers to corrupt heap memory via an unchecked subsong index in the GROOVES block. Attackers can craft a FamiTracker module with a subsong count of 2 or more to write a groove pattern past the subsong vector, crashing Furnace when opened.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/tildearrow/furnace/commit/c120c72391e3229fe258e5759f43427febcb8693

## Affected products and versions

- tildearrow / furnace (tildearrow/furnace): ≥ 0; ≤ 0.6.8.3 (affected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.9 (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; source: CNA: VulnCheck

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H; source: CNA: VulnCheck

- CVSS 4.0: 6.9 (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; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.14% as of 2026-11-05; percentile 3.06%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-129

## Exploit evidence

- exploit: https://hackmd.io/@haindpwn/furnace-ftm-import-notemap-and-groove-subsong-oob (ADP: CISA-ADP)

## References

- https://github.com/tildearrow/furnace/issues/2966 (CNA: VulnCheck; issue-tracking)

- https://github.com/tildearrow/furnace (CNA: VulnCheck; product)

- https://github.com/tildearrow/furnace/commit/c120c72391e3229fe258e5759f43427febcb8693 (CNA: VulnCheck; patch)

- https://github.com/tildearrow/furnace/blob/v0.6.8.3/src/engine/fileOps/ftm.cpp#L1597-L1605 (CNA: VulnCheck; technical-description)

- https://hackmd.io/@haindpwn/furnace-ftm-import-notemap-and-groove-subsong-oob (CNA: VulnCheck; third-party-advisory)

- https://www.vulncheck.com/advisories/furnace-through-0.6.8.3-out-of-bounds-write-via-famitracker-grooves-block-import (CNA: VulnCheck; third-party-advisory)

- https://hackmd.io/@haindpwn/furnace-ftm-import-notemap-and-groove-subsong-oob (ADP: CISA-ADP; exploit)

- https://github.com/tildearrow/furnace (disclosure@vulncheck.com)

- https://github.com/tildearrow/furnace/blob/v0.6.8.3/src/engine/fileOps/ftm.cpp#L1597-L1605 (disclosure@vulncheck.com)

- https://github.com/tildearrow/furnace/commit/c120c72391e3229fe258e5759f43427febcb8693 (disclosure@vulncheck.com)

- https://github.com/tildearrow/furnace/issues/2966 (disclosure@vulncheck.com)

- https://hackmd.io/@haindpwn/furnace-ftm-import-notemap-and-groove-subsong-oob (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/furnace-through-0.6.8.3-out-of-bounds-write-via-famitracker-grooves-block-import (disclosure@vulncheck.com)

- https://hackmd.io/@haindpwn/furnace-ftm-import-notemap-and-groove-subsong-oob (134c704f-9b21-4f2e-91b3-4a467353bcc0)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-116731; retrieved 2026-11-05; source updated 2026-11-05

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116731; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-116731; retrieved 2026-11-05; source updated Not reported

Revision: 7628300fe6d5c0bef470bc20c7b39702d47fc7b91b3997afcdd4a69a0804156a

Canonical: https://y2.dev/cve/CVE-2026-116731

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