CVE-2026-64085: hwmon: (pmbus/adm1266) bounce blackbox records through a protocol-sized buffer

High 7.8 EPSS 0.1% Linux kernel

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) bounce blackbox records through a protocol-sized buffer adm1266_pmbus_block_xfer() copies the device-supplied block payload into the caller-provided buffer using the device-supplied length: memcpy(data_r, &msgs[1].buf[1], msgs[1].buf[0]); The helper does not know how large data_r is and trusts the device to return at most one record's worth of bytes. adm1266_nvmem_read_blackbox() violates that contract: it advances read_buff inside data->dev_mem in ADM1266_BLACKBOX_SIZE (64-byte) strides while the helper is willing to write up to ADM1266_PMBUS_BLOCK_MAX (255) bytes. A device that returns more than 64 bytes on the trailing record (read_buff offset 1984 in the 2048-byte dev_mem allocation) overflows dev_mem by up to 191 bytes before the post-call if (ret != ADM1266_BLACKBOX_SIZE) return -EIO; can reject the response. Contain the fix in the caller without changing the helper signature: read each record into a 255-byte local bounce buffer that matches the helper's maximum output, validate the returned length, and only then copy exactly ADM1266_BLACKBOX_SIZE bytes into the dev_mem slot.

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

What to do now

  1. Check whether you run Linux kernel and which version (commands below).
  2. Install the fixed version for your system: see “Patch it” below.
  3. 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:

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

ReleasePackageStatusFixed version / advisory
Debian 12linuxfixed6.1.176-1
Debian 13linuxfixed6.12.94-1
Debian testinglinuxfixed7.0.12-1

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.