CVE-2026-121941
Received Received - Intake

Heap Buffer Overflow in libmt32emu MIDI Parser

Publication date: 2026-11-04

Last updated on: 2026-11-04

Assigner: VulnCheck

Description
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.

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Meta Information

Published
2026-11-04
Last Modified
2026-11-04
Generated
2026-11-04
AI Q&A
2026-11-04
EPSS Evaluated
N/A
NVD
CVE-2026-121941
EUVD
EUVD-2026-116898

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
munt libmt32emu 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-122 A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

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Executive Summary

libmt32emu before 2.8.4 has a heap buffer overflow in MidiStreamParserImpl::parseSysex. Attackers exploit this by sending oversized SysEx messages with more than 32768 bytes of data through the mt32emu_parse_stream API. This corrupts heap memory and can crash the application.

Detection Guidance

Detecting this vulnerability requires checking the version of libmt32emu. If your system uses libmt32emu before version 2.8.4, it is vulnerable. Run commands like 'apt list --installed | grep libmt32emu' or 'rpm -qa | grep libmt32emu' to check the installed version.

Impact Analysis

If you use software relying on libmt32emu (like MIDI players or sequencers), an attacker could crash your application by sending a maliciously crafted MIDI file or input. This may lead to denial of service or potential code execution in some cases.

Compliance Impact

This vulnerability does not directly impact GDPR or HIPAA compliance. However, if exploited to disrupt services processing personal data, it could indirectly affect availability requirements under these regulations.

Mitigation Strategies

Immediately update libmt32emu to version 2.8.4 or later. If updating is not possible, avoid processing untrusted MIDI files or using untrusted MIDI ports/sequencers until patched.

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