CVE-2026-63902 Details
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 ]
A vulnerability has been identified in the Linux kernel's USB serial Cypress M8 driver. The issue arises in the 'cypress_read_int_callback' function, which processes the interrupt-in buffer based on the chosen Cypress packet format. Format 1 requires a two-byte status/count header, while Format 2 needs a one-byte combined status/count header. The USB serial core allocates the interrupt-in buffer according to the endpoint descriptor's maximum packet size. However, successful interrupt transfers can be shorter than expected if the 'URB_SHORT_NOT_OK' flag is not set. This vulnerability allows for out-of-bounds reads of header bytes, as the driver does not properly validate the received packets before processing them. The kernel's AddressSanitizer (KASAN) has reported a slab-out-of-bounds error, indicating that the vulnerability could be exploited to read memory beyond the allocated buffer.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. Instructions for downloading the patched version are available on the official Linux kernel website.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No CVSS 3.x data is available for this CVE.
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
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Weakness Enumeration
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Affected Products
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Change History
1 change record found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 19, 2026 | New CVE Received | kernel.org |