CVE-2026-63898: USB: serial: mct_u232: 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: mct_u232: fix memory corruption with small endpoint The driver overrides the maximum transfer size for a specific device which only accepts 16 byte packets for its 32 byte bulk-out endpoint. Make sure to never increase the maximum transfer size to prevent slab corruption should a malicious device report a smaller endpoint max packet size than expected.

CVE-2026-63898CVE 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 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 94edbbc5fe00d03cfe1d4e690d7d2cd36317a935
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before bd2ddb3fe9052ad8703593bbec26ecc7ca92869e
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 39e295a91e80f3b91f61c7ada2bde434dcaba20d
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 90dbad14b109e5fdfb4934ff61e561d11ba3742d
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 6cb48f8890f9b2051d7c34823057296a536a31c5
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before d8fdf33d6fcfb90cbec26299baf2352c84b2d768
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 57f332af1745014cd7e40414814ffaa6bc7d3b5b
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 915b36d701950503c4ea0f6e314b10868e59fce3
Linux Linux 2.6.12

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`	out of support scope
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.