Description

In the Linux kernel, the following vulnerability has been resolved:

ALSA: ump: Fix buffer overflow at UMP SysEx message conversion

The conversion function from MIDI 1.0 to UMP packet contains an
internal buffer to keep the incoming MIDI bytes, and its size is 4, as
it was supposed to be the max size for a MIDI1 UMP packet data.
However, the implementation overlooked that SysEx is handled in a
different format, and it can be up to 6 bytes, as found in
do_convert_to_ump(). It leads eventually to a buffer overflow, and
may corrupt the memory when a longer SysEx message is received.

The fix is simply to extend the buffer size to 6 to fit with the SysEx
UMP message.

Classification

CVE ID: CVE-2025-37891

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 4.53% (scored less or equal to compared to others)

EPSS Date: 2025-06-17 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-37891
https://git.kernel.org/stable/c/ce4f77bef276e7d2eb7ab03a5d08bcbaa40710ec
https://git.kernel.org/stable/c/226beac5605afbb33f8782148d188b64396145a4
https://git.kernel.org/stable/c/42ef48dd4ebb082a1a90b5c3feeda2e68a9e32fe
https://git.kernel.org/stable/c/56f1f30e6795b890463d9b20b11e576adf5a2f77

Timeline