CVE-2025-37891

Kernel memory corruption via oversized UMP SysEx conversion

Published May 19, 2025 · Updated Aug 5, 2026

Buffer overflow in the ALSA UMP converter in Linux allows local users to corrupt kernel memory via a long UMP SysEx message. The MIDI 1.0-to-UMP conversion state allocates four bytes for incoming data, but do_convert_to_ump() copies SysEx payloads of up to six bytes into it. The required gate is low-privileged local access to a UMP-capable ALSA MIDI path; resulting corruption compromises confidentiality, integrity, and availability.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in the ALSA UMP converter in Linux allows local users to corrupt kernel memory via a long UMP SysEx message. The MIDI 1.0-to-UMP conversion state allocates four bytes for incoming data, but do_convert_to_ump() copies SysEx payloads of up to six bytes into it. The required gate is low-privileged local access to a UMP-capable ALSA MIDI path; resulting corruption compromises confidentiality, integrity, and availability.

The record

CVE
CVE-2025-37891
Published
May 19, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-120, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <226beac5605afbb33f8782148d188b64396145a4
  2. Affected versionversion=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <42ef48dd4ebb082a1a90b5c3feeda2e68a9e32fe
  3. Affected versionversion=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <56f1f30e6795b890463d9b20b11e576adf5a2f77
  4. Affected versionversion=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <ce4f77bef276e7d2eb7ab03a5d08bcbaa40710ec
  5. Affected versionversion=6.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <226beac5605afbb33f8782148d188b64396145a4; version=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <42ef48dd4ebb082a1a90b5c3feeda2e68a9e32fe; version=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <56f1f30e6795b890463d9b20b11e576adf5a2f77; version=0b5288f5fe63eab687c14e5940b9e0d532b129f2 <ce4f77bef276e7d2eb7ab03a5d08bcbaa40710ec; version=6.5

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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