CVE-2026-63899: USB: serial: mxuport: 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: mxuport: fix memory corruption with small endpoint Make sure that the bulk-out endpoint max packet size is at least eight bytes to avoid user-controlled slab corruption should a malicious device report a smaller size.

CVE-2026-63899CVE identifier
7.8CVSS 3.1 base score (high)
0.2%EPSS: chance of exploitation in the next 30 days (higher than 7% 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 ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before 086b858b5f5125bc9d967ea2bd825f83d9f8f29d
Linux Linux ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before 2f3661eb2446e1ef593da45e01a3b21a906768ec
Linux Linux ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before ccbec56f2f9af008f1574335cc6a668f16603e47
Linux Linux ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before be3a1ed4ae51fa8dde57383277d336ce834f2cd9
Linux Linux ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before e906545641d34fb1a09a65b4b5cfdff40eb09681
Linux Linux ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before 6c0cf56f00f280d72180bb6ce79741bc787a6269
Linux Linux ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before b40166b4ef96067620a0f248e74ad9658c8f680c
Linux Linux ee467a1f2066d2bfa293f7c2c7f1ff7000b0a39e to before 4085f0dbb1ce2251c9a5938d693de6593f0ab2bd
Linux Linux 3.14

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-0:5.14.0-687.59.1.el9_8`	fixed	`RHSA-2026:86033`
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 10	`kernel-0:6.12.0-211.66.1.el10_2`	fixed	`RHSA-2026:83207`

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.