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Linux KernelOperating system · Linux

CVE-2026-52963

MEDIUM · 5.5 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 4.5 / 4.10 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Bound MIDI endpoint descriptor scans snd_usbmidi_get_ms_info() validates the internal MIDIStreaming endpoint descriptor size before using baAssocJackID[], but the descriptor walker can still return a class-specific endpoint descriptor whose bLength exceeds the remaining bytes in the endpoint-extra scan. That leaves later flexible-array reads bounded by bLength, but not by the remaining bytes in the endpoint-extra scan. Stop walking when bLength is zero or extends past the remaining endpoint-extra scan.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Out-of-bounds read vulnerability in Linux kernel's ALSA USB audio driver where snd_usbmidi_get_ms_info() doesn't validate that MIDI endpoint descriptor bLength doesn't exceed remaining bytes in the endpoint-extra buffer before performing flexible-array reads, allowing access beyond buffer boundaries.

MitigationApply Linux kernel patch to add bounds checking that stops the descriptor walk when bLength is zero or extends past the remaining endpoint-extra scan; typically delivered via kernel updates.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.4.238, < 4.5>= 4.9.238, < 4.10>= 4.14.200, < 4.15>= 4.19.149, < 4.20>= 5.4.69, < 5.5>= 5.7, < 5.10.258>= 5.11, < 5.15.209>= 5.16, < 6.1.175>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify kernel version
    Run `uname -r` to get the running kernel version
    Affected if The kernel version falls within any of the affected ranges: >= 4.4.238 and < 4.5, >= 4.9.238 and < 4.10, >= 4.14.200 and < 4.15, >= 4.19.149 and < 4.20, >= 5.4.69 and < 5.5, >= 5.7 and < 5.10.258, >= 5.11 and < 5.15.209, >= 5.16 and < 6.1.175, >= 6.2 and < 6.6.141, >= 6.7 and < 6.12.91, >= 6.13 and
  2. Verify USB audio driver is present
    Check if the snd_usb_audio module is loaded with `lsmod | grep snd_usb` or check /proc/asound/cards for USB audio devices
    Affected if The snd_usb_audio kernel module is loaded or USB audio cards appear in /proc/asound/cards
  3. Check for connected USB MIDI devices
    Run `lsusb` or check /sys/bus/usb/devices for any USB MIDI class devices (class 01, subclass 03)
    Affected if Any USB MIDI devices are connected and the kernel is in an affected version range
  4. Inspect ALSA MIDI endpoints
    Check /proc/asound/*/midi0 or use `amidi -l` to list active MIDI ports originating from USB devices
    Affected if USB MIDI endpoints are enumerated by the ALSA driver and the kernel version is affected

A system is affected if it runs a kernel version within the listed ranges AND has USB MIDI devices connected that trigger the snd_usbmidi_get_ms_info() code path.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.5 / 4.10 / 4.15 or later
Fixed in 4.54.104.15
Vendor patch git.kernel.org →
Interim mitigation

Apply Linux kernel patch to add bounds checking that stops the descriptor walk when bLength is zero or extends past the remaining endpoint-extra scan; typically delivered via kernel updates.

Recommended fix Moderate confidence

Linux kernel 4.5, 4.10, 4.15, or 4.20 (depending on which branch was affected)

  1. Identify the current running kernel version using 'uname -r'
  2. Determine which affected kernel branch (4.4.x, 4.9.x, 4.14.x, or 4.19.x) is in use
  3. Upgrade the Linux kernel to the first fixed version in that branch: for 4.4.x upgrade to 4.5 or later, for 4.9.x upgrade to 4.10 or later, for 4.14.x upgrade to 4.15 or later, for 4.19.x upgrade to 4.20 or later
  4. After kernel upgrade, reboot the system to load the fixed kernel
  5. Verify the new kernel version is running with 'uname -r'
Caveat Kernel upgrades may require rebuilding out-of-tree kernel modules; ensure compatible drivers are available for the new kernel version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-52963 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data