Buffer overflow in Munt Libmt32emu
CVE-2026-121941
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/munt/munt/issues/149 (issue-tracking)
- hackmd.io/@haindpwn/munt-midistreamparser-oversized-sysex-heap-overflow (third-party-advisory)
- github.com/munt/munt/commit/1749f7fed5cdb3a9015acce076a1512b1615dc3b (patch)
- github.com/munt/munt/blob/libmt32emu_2_8_3/mt32emu/src/MidiStreamParser.cpp (technical-description)
- VulnCheck Advisory: libmt32emu before 2.8.4 Heap Buffer Overflow via MidiStreamParserImpl::parseSysex (third-party-advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0
Frequently asked questions
- What is CVE-2026-121941?
- CVE-2026-121941 is a high-severity vulnerability in Munt Libmt32emu, classified under Heap-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-11-04.
- How severe is CVE-2026-121941?
- High severity. CVSS v3 base score is 7.8 out of 10.