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CVE-2026-121941libmt32emu before 2.8.4 Heap Buffer Overflow via MidiStreamParserImpl::parseSysex
libmt32emu before 2.8.4 contains a heap buffer overflow vulnerability in MidiStreamParserImpl::parseSysex that allows attackers to write past a heap allocation by supplying oversized unterminated SysEx messages. Attackers can feed more than 32768 SysEx data bytes through the mt32emu_parse_stream API via MIDI files, ports, or sequencer clients to corrupt heap memory and crash the application.
8.5 HIGHEPSS 0.26%Not in KEVNVD: Received
Overview
Severity
| Score | Severity | Version | Vector String |
|---|---|---|---|
| 8.5 | HIGH | 4.0VulnCheck (CNA) | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| 7.8 | HIGH | 3.1VulnCheck (CNA) | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
Details
- CVE ID
- CVE-2026-121941
- Status
- Received
- Assigner (CNA)
- VulnCheck
- Published
- Nov 4, 2026
- Last modified
- 2026-11-04 21:18 UTC
- Weaknesses
- CWE-122 · Heap-based Buffer Overflow
Affected Products
As published by the CNA in the CVE record.
muntlibmt32emu1 version range
- before 2.8.4
References
- github.com https://github.com/munt/munt/blob/libmt32emu_2_8_3/mt32emu/src/MidiStreamParser.cpp#L223-L257
- github.com https://github.com/munt/munt/commit/1749f7fed5cdb3a9015acce076a1512b1615dc3b
- github.com https://github.com/munt/munt/issues/149
- hackmd.io https://hackmd.io/@haindpwn/munt-midistreamparser-oversized-sysex-heap-overflow
- vulncheck.com https://www.vulncheck.com/advisories/libmt32emu-before-2.8.4-heap-buffer-overflow-via-midistreamparserimpl-parsesysex
- hackmd.io https://hackmd.io/@haindpwn/cve-2026-121941-munt-midistreamparser-oversized-sysex-heap-overflow