CVE-2026-63956: USB: serial: cypress_m8: fix memory corruption with small endpoint

High 7.8 EPSS 0.2% Linux kernel

In the Linux kernel, the following vulnerability has been resolved: USB: serial: cypress_m8: fix memory corruption with small endpoint Make sure that the interrupt-out endpoint max packet size is at least eight bytes to avoid user-controlled slab corruption or NULL-pointer dereference should a malicious device report a smaller size.

CVE-2026-63956CVE identifier
7.8CVSS 3.1 base score (high)
0.2%EPSS: chance of exploitation in the next 30 days (higher than 6% of CVEs)
2026-07-19published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

What to do now

Check whether you run Linux kernel and which version (commands below).
Install the fixed version for your system: see “Patch it” below.
Reboot into the new kernel (uname -r to confirm); live patching (kpatch, Ubuntu Livepatch, SUSE kGraft/klp) can defer the reboot for some CVEs

Affected and fixed versions

Affected:

Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before 4fcb22218f0a7229b7ce3b3952fb644def293fa5
Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before ad3d1628a46134276546d7a12fedf04be9979158
Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before 52e18ae0c47c5c89e18fcd8022f287f7cc8802ec
Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before 4bcaa59f403dbde6328604a500d65ee8d40975d9
Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before 1ef25704bd3b625fd151c09feee459479f71ee64
Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before 284105c40fc31fff90cdab8a0377aaeb92f87f0e
Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before 6c13f3bb652bc8665e709ba07122612586aea648
Linux Linux 3416eaa1f8f8d516b77de514e14cf8da256d28fb to before e1a9d791fd66ab2431b9e6f6f835823809869047
Linux Linux 2.6.26

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

Debian

sudo apt update
sudo apt install --only-upgrade linux-image-amd64

Ubuntu

sudo apt update
sudo apt install --only-upgrade linux-image-generic (or the installed flavour: linux-image-aws, -azure, -gcp, -virtual)

RHEL, AlmaLinux, Rocky, Oracle

sudo dnf upgrade --refresh kernel

Fedora

sudo dnf upgrade --refresh kernel

SUSE / openSUSE

sudo zypper refresh
sudo zypper update kernel-default

Amazon Linux

sudo dnf upgrade --releasever=latest kernel kernel6.12

Arch Linux

sudo pacman -Syu

Alpine

apk update && apk upgrade linux-lts linux-virt

FreeBSD

not Linux

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

Fix status in Linux distributions

Release	Package	Status	Fixed version / advisory
Debian 12	`linux`	fixed	`6.1.176-1`
Debian 13	`linux`	fixed	`6.12.94-1`
Debian testing	`linux`	fixed	`7.0.12-1`
Red Hat Enterprise Linux 9	`kernel`	affected
Red Hat Enterprise Linux 9	`kernel-rt`	affected
Red Hat Enterprise Linux 8	`kernel`	affected
Red Hat Enterprise Linux 8	`kernel-rt`	affected
Red Hat Enterprise Linux 7	`kernel`	affected
Red Hat Enterprise Linux 7	`kernel-rt`	affected
Red Hat Enterprise Linux 6	`kernel`	affected
Red Hat Enterprise Linux 10	`kernel`	affected

From the Debian security tracker, Ubuntu CVE tracker and Red Hat Security Data API, refreshed every few hours.

Sources

Page generated automatically from official sources on 2026-11-03 18:05 UTC. Always confirm with your vendor's advisory.