munt libmt32emu up to 2.8.3 MidiStreamParser parseSysex heap-based overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.4$0-$5k2.05

Summaryinfo

A vulnerability, which was classified as critical, has been found in munt libmt32emu up to 2.8.3. Affected by this issue is the function MidiStreamParserImpl::parseSysex of the component MidiStreamParser. This manipulation causes heap-based overflow. This vulnerability is tracked as CVE-2026-121941. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in munt libmt32emu up to 2.8.3. Affected by this vulnerability is the function MidiStreamParserImpl::parseSysex of the component MidiStreamParser. The manipulation with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is 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(). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-121941 since 11/04/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.8.4 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-116898). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (VulnCheck): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: libmt32emu 2.8.4

Timelineinfo

11/04/2026 Advisory disclosed
11/04/2026 +0 days CVE reserved
11/04/2026 +0 days VulDB entry created
11/04/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CNA: VulnCheck
CVE: CVE-2026-121941 (🔒)

GCVE (CVE): GCVE-0-2026-121941
GCVE (VulDB): GCVE-100-431047
EUVD: 🔒

Entryinfo

Created: 11/04/2026 13:40
Updated: 11/04/2026 14:30
Changes: 11/04/2026 13:40 (77), 11/04/2026 14:30 (1)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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