CVE-2026-63902: Linux Vulnerability

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 ]

Metrics

EPSS Probability

0.21%

11.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < fcef31a5a85ccf3c313449a866ec6ed7e4132425; >= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < aaa66708bfb1dca2acd219d1c1582f9f6d5492cb; >= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < 44f9bab8df7750a1e2a4d6cc22d7c9c2dc096aed; >= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < be50533fe7068e86eb7adb81988e6d6a3f6dfe53; >= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < 90664556916de22467097d4c8ceb716d597a5c32; >= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < ae03453f2c809ca3cf73753269fa6184dea7160f; >= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < 4a4cb0021ebe1fcadb52e04d19ed8d71470a530b; >= 3416eaa1f8f8d516b77de514e14cf8da256d28fb, < 9f9bfc80c67f35a275820da7e83a35dface08281
Linux	Linux	2.6.26

References

Timeline

Published: Jul 19, 2026
Last Modified: Jul 27, 2026
Status: Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-63902?

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 ]

How severe is CVE-2026-63902?

Severity scoring for CVE-2026-63902 is pending analysis. The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-63902?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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