CVE-2026-63902

USB: serial: cypress_m8: validate interrupt packet headers

Published Jul 19, 2026 CVSS 3.1 · 7.1 High EPSS < 1% KEV · Not listed

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 ]

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< fcef31a5a85ccf3c313449a866ec6ed7e4132425
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< aaa66708bfb1dca2acd219d1c1582f9f6d5492cb
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< 44f9bab8df7750a1e2a4d6cc22d7c9c2dc096aed
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< be50533fe7068e86eb7adb81988e6d6a3f6dfe53
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< 90664556916de22467097d4c8ceb716d597a5c32
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< ae03453f2c809ca3cf73753269fa6184dea7160f
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< 4a4cb0021ebe1fcadb52e04d19ed8d71470a530b
`3416eaa1f8f8d516b77de514e14cf8da256d28fb`	affected	< 9f9bfc80c67f35a275820da7e83a35dface08281

Linux

affected

Version	Status	Constraints
`2.6.26`	affected	—
`0`	unaffected	< 2.6.26
`5.10.259`	unaffected	≤ 5.10.*
`5.15.210`	unaffected	≤ 5.15.*
`6.1.176`	unaffected	≤ 6.1.*
`6.6.143`	unaffected	≤ 6.6.*
`6.12.93`	unaffected	≤ 6.12.*
`6.18.35`	unaffected	≤ 6.18.*
`7.0.12`	unaffected	≤ 7.0.*
`7.1`	unaffected	≤ *

Configuration 1 [-]

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc1::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc2::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc3::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc4::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc5::::::

No data.

Vendor Product Versions

Linux

Linux Kernel

Version	Status	Scheme	Platform
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,fcef31a5a85ccf3c313449a866ec6ed7e4132425)`	affected	code_commit	—
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,aaa66708bfb1dca2acd219d1c1582f9f6d5492cb)`	affected	code_commit	—
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,44f9bab8df7750a1e2a4d6cc22d7c9c2dc096aed)`	affected	code_commit	—
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,be50533fe7068e86eb7adb81988e6d6a3f6dfe53)`	affected	code_commit	—
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,90664556916de22467097d4c8ceb716d597a5c32)`	affected	code_commit	—
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,ae03453f2c809ca3cf73753269fa6184dea7160f)`	affected	code_commit	—
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,4a4cb0021ebe1fcadb52e04d19ed8d71470a530b)`	affected	code_commit	—
`[3416eaa1f8f8d516b77de514e14cf8da256d28fb,9f9bfc80c67f35a275820da7e83a35dface08281)`	affected	code_commit	—

Linux

Linux Kernel

Version	Status	Scheme	Platform
`2.6.26`	affected	semver	—
`[0,2.6.26)`	unaffected	semver	—
`[5.10.259,5.11.0)`	unaffected	semver	—
`[5.15.210,5.16.0)`	unaffected	semver	—
`[6.1.176,6.2.0)`	unaffected	semver	—
`[6.6.143,6.7.0)`	unaffected	semver	—
`[6.12.93,6.13.0)`	unaffected	semver	—
`[6.18.35,6.19.0)`	unaffected	semver	—
`[7.0.12,7.1.0)`	unaffected	semver	—
`[7.1,*]`	unaffected	semver	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
Ubuntu USN	USN-8593-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8603-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8618-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8663-1	Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN	USN-8664-1	Linux kernel (NVIDIA BaseOS) vulnerabilities
Ubuntu USN	USN-8728-1	Linux kernel (GCP) vulnerabilities
Ubuntu USN	USN-8728-2	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8728-3	Linux kernel (Oracle) vulnerabilities
Ubuntu USN	USN-8875-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8877-1	Linux kernel (GCP) vulnerabilities
Ubuntu USN	USN-8878-1	Linux kernel (GCP) vulnerabilities
Ubuntu USN	USN-8879-1	Linux kernel (Oracle) vulnerabilities
Ubuntu USN	USN-8903-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8904-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8905-1	Linux kernel (GCP) vulnerabilities
Ubuntu USN	USN-8906-1	Linux kernel (IBM) vulnerabilities
Ubuntu USN	USN-8875-2	Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN	USN-8903-2	Linux kernel vulnerabilities
Ubuntu USN	USN-8905-2	Linux kernel (GCP) vulnerabilities
Ubuntu USN	USN-9002-1	Linux kernel (NVIDIA Tegra) vulnerabilities
Ubuntu USN	USN-9025-1	Linux kernel vulnerabilities
Ubuntu USN	USN-9029-1	Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN	USN-9066-1	Linux kernel (HWE) vulnerabilities

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.171% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/44f9bab8df7750a1e2a4d6cc22d7c9c2dc096aed
https://git.kernel.org/stable/c/4a4cb0021ebe1fcadb52e04d19ed8d71470a530b
https://git.kernel.org/stable/c/90664556916de22467097d4c8ceb716d597a5c32
https://git.kernel.org/stable/c/9f9bfc80c67f35a275820da7e83a35dface08281
https://git.kernel.org/stable/c/aaa66708bfb1dca2acd219d1c1582f9f6d5492cb
https://git.kernel.org/stable/c/ae03453f2c809ca3cf73753269fa6184dea7160f
https://git.kernel.org/stable/c/be50533fe7068e86eb7adb81988e6d6a3f6dfe53
https://git.kernel.org/stable/c/fcef31a5a85ccf3c313449a866ec6ed7e4132425
https://lore.kernel.org/linux-cve-announce/2026071944-CVE-2026-63902-68cb@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-63902
https://www.cve.org/CVERecord?id=CVE-2026-63902

History

Oct 30, 2026 2:45 PM Affected versions updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
CPEs		cpe:2.3:o:linux:linux_kernel:7.1:rc1:::::: cpe:2.3:o:linux:linux_kernel:7.1:rc2:::::: cpe:2.3:o:linux:linux_kernel:7.1:rc3:::::: cpe:2.3:o:linux:linux_kernel:7.1:rc4:::::: cpe:2.3:o:linux:linux_kernel:7.1:rc5::::::
Metrics	cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}`	cvssV3_1 `{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'}`

Jul 22, 2026 12:15 AM Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
References		https://lore.kernel.org/linux-cve-announce/2026071944-CVE-2026-63902-68cb@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-63902 https://www.cve.org/CVERecord?id=CVE-2026-63902
Metrics	threat_severity `None`	cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}` threat_severity `Moderate`

Jul 22, 2026 12:00 AM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-125

Jul 19, 2026 3:30 PM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

Type	Values Removed	Values Added
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 ]
Title		USB: serial: cypress_m8: validate interrupt packet headers
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/44f9bab8df7750a1e2a4d6cc22d7c9c2dc096aed https://git.kernel.org/stable/c/4a4cb0021ebe1fcadb52e04d19ed8d71470a530b https://git.kernel.org/stable/c/90664556916de22467097d4c8ceb716d597a5c32 https://git.kernel.org/stable/c/9f9bfc80c67f35a275820da7e83a35dface08281 https://git.kernel.org/stable/c/aaa66708bfb1dca2acd219d1c1582f9f6d5492cb https://git.kernel.org/stable/c/ae03453f2c809ca3cf73753269fa6184dea7160f https://git.kernel.org/stable/c/be50533fe7068e86eb7adb81988e6d6a3f6dfe53 https://git.kernel.org/stable/c/fcef31a5a85ccf3c313449a866ec6ed7e4132425