CVE-2025-37891: ALSA: ump: Fix buffer overflow at UMP SysEx message conversion
Vulnerability summary
CVE-2025-37891 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 15.8% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 38 · Related 33Timeline
- 19-05-2025PublishedVulnerability first disclosed.
- 15-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
16%
Versus all other CVEs
30-day change
Increase +0.02 pp
From 0.23% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu118 products
- linux< 6.8.0-100.100
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 6.8.0-1046.49
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 0b5288f5fe63eab687c14e5940b9e0d532b129f2, < ce4f77bef276e7d2eb7ab03a5d08bcbaa40710ec | ≥ 0b5288f5fe63eab687c14e5940b9e0d532b129f2, < 226beac5605afbb33f8782148d188b64396145a4 | ≥ 0b5288f5fe63eab687c14e5940b9e0d532b129f2, < 42ef48dd4ebb082a1a90b5c3feeda2e68a9e32fe | ≥ 0b5288f5fe63eab687c14e5940b9e0d532b129f2, < 56f1f30e6795b890463d9b20b11e576adf5a2f77 | 6.5
- linux_kernel≥ 6.5, < 6.6.90 | ≥ 6.7, < 6.12.28 | ≥ 6.13, < 6.14.6 | 6.15:rc1 | 6.15:rc2 | 6.15:rc3 | 6.15:rc4
Debian1 product
- linux< 6.12.29-1
3 vendors · 121 products
