CVE-2026-63897

Kernel-memory disclosure via short USB interrupt packets

Published Jul 19, 2026 · Updated Jul 19, 2026

Out-of-bounds read in the mct_u232 USB serial driver in the Linux Kernel allows physically proximate attackers to expose kernel memory. The mct_u232_read_int_callback function interprets data[0] and data[1] without first ensuring that the interrupt transfer contains two bytes, so stale or uninitialized slab data reaches user space. A crafted short interrupt-in packet from a connected MCT U232-compatible USB device is required, and the reported consequence is limited to information disclosure.

CVSS severity2.4
Low
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

Out-of-bounds read in the mct_u232 USB serial driver in the Linux Kernel allows physically proximate attackers to expose kernel memory. The mct_u232_read_int_callback function interprets data[0] and data[1] without first ensuring that the interrupt transfer contains two bytes, so stale or uninitialized slab data reaches user space. A crafted short interrupt-in packet from a connected MCT U232-compatible USB device is required, and the reported consequence is limited to information disclosure.

The record

CVE
CVE-2026-63897
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1200
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <245aba83e3c288e176ed037a1f6b618b09e92ed8
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <631b8b7c456567f7a8d26f6fc354c8dd9cc9f832
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <70bb9a2661d34b93a9b83cf83e2b76289a712ef0
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <82b48d70bced1ec8e5f676d1fd5eccc7a44dc418
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8b93ee5baeef6efabee2c3381907733ad2dbc883
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a093f3e0c03d25a86d747a655d4b9322ffb2ed87
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ed260b56bc9fc878e5dcbb866eab8af0688e0e67
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f06bcaba29707f060706483b2020d3cafbe98f9f
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <245aba83e3c288e176ed037a1f6b618b09e92ed8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <631b8b7c456567f7a8d26f6fc354c8dd9cc9f832; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <70bb9a2661d34b93a9b83cf83e2b76289a712ef0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <82b48d70bced1ec8e5f676d1fd5eccc7a44dc418; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8b93ee5baeef6efabee2c3381907733ad2dbc883; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a093f3e0c03d25a86d747a655d4b9322ffb2ed87; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ed260b56bc9fc878e5dcbb866eab8af0688e0e67; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f06bcaba29707f060706483b2020d3cafbe98f9f; version=2.6.12

Published CVSS scores

2.4SUSECVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
2.4SUSECVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1200Hardware Additions

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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