CVE-2026-64381: smb: client: Fix next buffer leak in receive_encrypted_standard()

High 7.8 EPSS 0.1% Linux kernel

In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix next buffer leak in receive_encrypted_standard() receive_encrypted_standard() allocates next_buffer before checking whether the number of compound PDUs already reached MAX_COMPOUND. If the limit check fails, the function returns immediately and the newly allocated next_buffer is not assigned to server->smallbuf/server->bigbuf, making it leaked. Move the MAX_COMPOUND check before allocating next_buffer.

CVE-2026-64381CVE identifier
7.8CVSS 3.1 base score (high)
0.1%EPSS: chance of exploitation in the next 30 days (higher than 3% of CVEs)
2026-07-25published

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 b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 94e4f672db029414b9888b5137a7559f1febf2d8
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 68fc0b6cc03ca58060c0f36454e169f5fe258974
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 07e0ab81df1790afa35732a4e8e07ff831b29008
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 9136a08dc29328edd9867f2545e73906ac9df93b
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 67097772df7791c53d608f04bd31c676ccf79b83
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 297243e365fc9fe2f8e9b7dd535a65d922cd108b
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 927d4805aea0a287d36dd4f826ee24d69a2afee3
Linux Linux b24df3e30cbf48255db866720fb71f14bf9d2f39 to before 1c6267a1d5cf4c73b656f8181b310cbbb3e4767b
Linux Linux 4.19

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	`6.1.180-1`
Debian 13	`linux`	fixed	`6.12.96-1`
Debian testing	`linux`	fixed	`7.1.4-1`
Debian 12	`linux-6.12`	fixed	`6.12.100-1~deb12u1`
Red Hat Enterprise Linux 9	`kernel`	fix deferred
Red Hat Enterprise Linux 9	`kernel-rt`	fix deferred
Red Hat Enterprise Linux 8	`kernel`	fix deferred
Red Hat Enterprise Linux 8	`kernel-rt`	fix deferred
Red Hat Enterprise Linux 10	`kernel`	fix deferred

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.