CVE-2026-121941
libmt32emu before 2.8.4 Heap Buffer Overflow via MidiStreamParserImpl::parseSysex
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.
INFO
Published Date :
Nov. 4, 2026, 1:17 p.m.
Last Modified :
Nov. 4, 2026, 1:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-121941
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update libmt32emu to version 2.8.4 or later.
- Ensure proper input validation for SysEx messages.
- Avoid processing oversized SysEx data.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-121941.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-121941 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-121941
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-121941 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-121941 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Nov. 04, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/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 Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-122 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/121xxx/CVE-2026-121941.json">CVE-2026-121941</a> Added Reference https://github.com/munt/munt/blob/libmt32emu_2_8_3/mt32emu/src/MidiStreamParser.cpp#L223-L257 Added Reference https://github.com/munt/munt/commit/1749f7fed5cdb3a9015acce076a1512b1615dc3b Added Reference https://github.com/munt/munt/issues/149 Added Reference https://hackmd.io/@haindpwn/munt-midistreamparser-oversized-sysex-heap-overflow Added Reference https://www.vulncheck.com/advisories/libmt32emu-before-2.8.4-heap-buffer-overflow-via-midistreamparserimpl-parsesysex