CVE-2025-37891 (GCVE-0-2025-37891)

Vulnerability from cvelistv5 – Published: 2025-05-19 07:19 – Updated: 2026-08-05 11:58
VLAI
Title
ALSA: ump: Fix buffer overflow at UMP SysEx message conversion
Summary
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.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 0b5288f5fe63eab687c14e5940b9e0d532b129f2 , < ce4f77bef276e7d2eb7ab03a5d08bcbaa40710ec (git)
Affected: 0b5288f5fe63eab687c14e5940b9e0d532b129f2 , < 226beac5605afbb33f8782148d188b64396145a4 (git)
Affected: 0b5288f5fe63eab687c14e5940b9e0d532b129f2 , < 42ef48dd4ebb082a1a90b5c3feeda2e68a9e32fe (git)
Affected: 0b5288f5fe63eab687c14e5940b9e0d532b129f2 , < 56f1f30e6795b890463d9b20b11e576adf5a2f77 (git)
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Linux Linux Affected: 6.5
Unaffected: 0 , < 6.5 (semver)
Unaffected: 6.6.90 , ≤ 6.6.* (semver)
Unaffected: 6.12.28 , ≤ 6.12.* (semver)
Unaffected: 6.14.6 , ≤ 6.14.* (semver)
Unaffected: 6.15 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: ump: Fix buffer overflow at UMP SysEx message conversion\n\nThe conversion function from MIDI 1.0 to UMP packet contains an\ninternal buffer to keep the incoming MIDI bytes, and its size is 4, as\nit was supposed to be the max size for a MIDI1 UMP packet data.\nHowever, the implementation overlooked that SysEx is handled in a\ndifferent format, and it can be up to 6 bytes, as found in\ndo_convert_to_ump().  It leads eventually to a buffer overflow, and\nmay corrupt the memory when a longer SysEx message is received.\n\nThe fix is simply to extend the buffer size to 6 to fit with the SysEx\nUMP message."
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              "value": "AV:L - The overflow is triggered by writing a MIDI 1.0 SysEx byte stream to the legacy rawmidi character device (/dev/snd/midiCxDy) that sound/core/ump.c creates for every UMP endpoint, reached via process_legacy_output() from an ordinary write(2). The alternate f_midi2 USB-gadget path is physical, but the local rawmidi path requires only local system access.\nAC:L - The attacker deterministically triggers the overflow by writing 0xF0 followed by five or more data bytes; the fifth byte directly overwrites the low byte of cvt-\u003elen, giving the attacker a chosen write offset with no race, no memory-layout guessing, and no retry logic.\nPR:L - Only an unprivileged local account with access to the ALSA MIDI device node is needed (audio group or active-seat uaccess ACL; an app with MIDI access on Android) \u2014 no capabilities, no root, and no privileged ioctl on the path.\nUI:N - The attacker writes to the MIDI device directly; no victim action is required. The presence of a UMP endpoint is an environmental precondition the attacker can satisfy themselves by attaching a USB MIDI 2.0 device or using an existing gadget/MIDI 2.0 interface.\nS:U - The corruption is confined to kernel heap memory within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - Attacker-controlled corruption of adjacent kmalloc-4k slab objects yields a read primitive by overwriting neighbouring length/pointer/index fields, and cvt_legacy_sysex_to_ump() additionally reads far out of bounds past the struct when a huge cvt-\u003elen is flushed.\nI:H - This is an unbounded linear out-of-bounds heap write with fully attacker-chosen data (one byte per SysEx byte, at an attacker-chosen starting offset), a classic slab-overflow primitive that can corrupt adjacent kernel objects and be escalated to arbitrary write and control-flow hijack.\nA:H - Walking off the end of the out_cvts allocation reliably corrupts slab metadata and neighbouring objects, causing oops/panic; the same write also destroys the converter\u0027s own state, so a trivial long SysEx message crashes the kernel."
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    "dateReserved": "2025-04-16T04:51:23.963Z",
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It leads eventually to a buffer overflow, and\\nmay corrupt the memory when a longer SysEx message is received.\\n\\nThe fix is simply to extend the buffer size to 6 to fit with the SysEx\\nUMP message.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ALSA: ump: Se corrige el desbordamiento del b\u00fafer en la conversi\u00f3n de mensajes SysEx de UMP. La funci\u00f3n de conversi\u00f3n de paquetes MIDI 1.0 a UMP contiene un b\u00fafer interno para almacenar los bytes MIDI entrantes, y su tama\u00f1o es de 4, ya que se supon\u00eda que era el tama\u00f1o m\u00e1ximo para los datos de un paquete MIDI1 UMP. Sin embargo, la implementaci\u00f3n pas\u00f3 por alto que SysEx se maneja en un formato diferente, y puede tener hasta 6 bytes, como se encuentra en do_convert_to_ump(). Eventualmente conduce a un desbordamiento del b\u00fafer y puede da\u00f1ar la memoria cuando se recibe un mensaje SysEx m\u00e1s largo. La soluci\u00f3n es simplemente extender el tama\u00f1o del b\u00fafer a 6 para que se ajuste al mensaje SysEx UMP.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"include/sound/ump_convert.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"0b5288f5fe63eab687c14e5940b9e0d532b129f2\",\"lessThan\":\"ce4f77bef276e7d2eb7ab03a5d08bcbaa40710ec\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0b5288f5fe63eab687c14e5940b9e0d532b129f2\",\"lessThan\":\"226beac5605afbb33f8782148d188b64396145a4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0b5288f5fe63eab687c14e5940b9e0d532b129f2\",\"lessThan\":\"42ef48dd4ebb082a1a90b5c3feeda2e68a9e32fe\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0b5288f5fe63eab687c14e5940b9e0d532b129f2\",\"lessThan\":\"56f1f30e6795b890463d9b20b11e576adf5a2f77\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"include/sound/ump_convert.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.5\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.5\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.90\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.28\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.14.6\",\"lessThanOrEqual\":\"6.14.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.15\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-120\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.5\",\"versionEndExcluding\":\"6.6.90\",\"matchCriteriaId\":\"A65F1BCF-45FE-4A18-A118-FB749AD97BBF\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.7\",\"versionEndExcluding\":\"6.12.28\",\"matchCriteriaId\":\"5082CE19-0F3D-4521-AB3E-810D8255F500\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13\",\"versionEndExcluding\":\"6.14.6\",\"matchCriteriaId\":\"19E5095E-5950-43EA-8E78-FC860855293F\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"8D465631-2980-487A-8E65-40AE2B9F8ED1\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"4C9D071F-B28E-46EC-AC61-22B913390211\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"13FC0DDE-E513-465E-9E81-515702D49B74\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"8C7B5B0E-4EEB-48F5-B4CF-0935A7633845\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/226beac5605afbb33f8782148d188b64396145a4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/42ef48dd4ebb082a1a90b5c3feeda2e68a9e32fe\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/56f1f30e6795b890463d9b20b11e576adf5a2f77\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/ce4f77bef276e7d2eb7ab03a5d08bcbaa40710ec\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}",
    "redhat_vex": {
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      "current_release_date": "2026-07-30T09:28:57+00:00",
      "cve": "CVE-2025-37891",
      "id": "CVE-2025-37891",
      "initial_release_date": "2025-05-19T00:00:00+00:00",
      "product_status:fixed": "891",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: ALSA: ump buffer overflow via malformed UMP SysEx message",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-37891.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-25T00:55:08Z",
      "cve": "CVE-2025-37891",
      "id": "CVE-2025-37891",
      "initial_release_date": "2025-05-20T01:07:46Z",
      "product_status:known_affected": "410",
      "product_status:known_not_affected": "307",
      "product_status:recommended": "407",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-37891",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-37891.json",
      "version": "45"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.