CVE-2026-63902

Public on 2026-07-19
Modified on 2026-07-24
Description
In the Linux kernel, the following vulnerability has been resolved:

USB: serial: cypress_m8: validate interrupt packet headers

cypress_read_int_callback() parses the interrupt-in buffer according to
the selected Cypress packet format. Format 1 has a two-byte status/count
header and format 2 has a one-byte combined status/count header. The
usb-serial core sizes the interrupt-in buffer from the endpoint
descriptor's wMaxPacketSize, and successful interrupt transfers can
complete short when URB_SHORT_NOT_OK is not set.

Check that the completed packet contains the selected header before
reading it. Malformed short reports are ignored and the interrupt URB is
resubmitted through the existing retry path, preventing out-of-bounds
header-byte reads.

KASAN report as below:
KASAN slab-out-of-bounds in cypress_read_int_callback+0x240/0x7f0
Read of size 1
Call trace:
cypress_read_int_callback() (drivers/usb/serial/cypress_m8.c:1009)
__usb_hcd_giveback_urb()
dummy_timer()

[ johan: use constants in header length sanity checks ]
Severity
Low severity
Low
See what this means
CVSS v3 Base Score
3.5
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2 - Core kernel Pending Fix
Amazon Linux 2 - Kernel-5.10 Extra kernel Pending Fix
Amazon Linux 2 - Kernel-5.4 Extra kernel Pending Fix
Amazon Linux 2 - Kernel-5.15 Extra kernel Not Affected
Amazon Linux 2023 kernel Not Affected
Amazon Linux 2023 kernel6.12 Not Affected
Amazon Linux 2023 kernel6.18 Not Affected

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 3.5 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L