CVE-2026-68219 Overview
CVE-2026-68219 is a vulnerability in the Linux kernel's NXP i.MX8 Image Sensor Interface (ISI) media driver. The imx8-isi driver fails to validate the minimum value of the downscaling factor before applying it to hardware. The ISI supports a maximum downscaling factor of 16, but no lower bound is enforced. Local users can trigger a state where the process becomes unresponsive, and even Ctrl+C fails to terminate it. The flaw affects confidentiality, integrity, and availability on systems that expose the imx8-isi V4L2 device to unprivileged users.
Critical Impact
A local low-privileged user can send crafted V4L2 scaling parameters to the imx8-isi driver, causing hangs and potential out-of-bounds behavior in kernel space.
Affected Products
- Linux kernel builds including the drivers/media/platform/nxp/imx8-isi driver
- NXP i.MX8 platforms using the ISI media pipeline
- Downstream distributions shipping unpatched kernel versions referenced in the upstream stable trees
Discovery Timeline
- 2026-08-10 - CVE-2026-68219 published to NVD
- 2026-08-13 - Last updated in NVD database
Technical Details for CVE-2026-68219
Vulnerability Analysis
The vulnerability resides in the NXP imx8-isi media driver, which handles image scaling for the i.MX8 ISI hardware block. The driver accepts a downscaling factor supplied through the V4L2 interface and programs it into hardware registers. The maximum supported factor is 16, but the code applied the setting without checking for a minimum value. When a caller supplies a value outside the valid range, the driver programs invalid scaling parameters. This causes the associated process to become unresponsive to signals, including SIGINT from Ctrl+C.
The issue is categorized as an out-of-bounds condition affecting kernel-mode processing of user-controlled scaling parameters. The local attack vector requires access to the ISI device node, typically /dev/video*, which on affected platforms may be readable by users in the video group.
Root Cause
The root cause is missing input validation. The driver applied user-supplied downscaling values to hardware without enforcing a minimum constraint. Upstream patches add the missing bounds check before writing the value to the ISI configuration registers.
Attack Vector
Exploitation requires local access with permission to open the ISI video device. An attacker issues a V4L2 VIDIOC_S_SELECTION or equivalent ioctl with a scaling parameter that falls below the required minimum. The driver programs the invalid setting, and the calling process enters an unrecoverable state. The vulnerability mechanism is described in the upstream commit messages referenced below; no verified public exploit code is available.
See the Linux Kernel Patch 28ae75d and Linux Kernel Patch 690cdda7 for the technical fix.
Detection Methods for CVE-2026-68219
Indicators of Compromise
- Processes holding open handles to /dev/video* on i.MX8 platforms that become unkillable and do not respond to SIGINT or SIGTERM.
- Kernel log entries from the imx8-isi driver showing invalid scaling configuration or hardware programming failures.
- Unexpected V4L2 ioctl calls from non-media applications targeting ISI device nodes.
Detection Strategies
- Inventory kernel versions across NXP i.MX8-based Linux fleets and correlate against the fixed commits listed in the upstream patches.
- Monitor auditd for ioctl calls against /dev/video* originating from unexpected users or binaries.
- Alert on processes stuck in uninterruptible sleep (D state) that reference the imx8-isi driver in /proc/<pid>/stack.
Monitoring Recommendations
- Ship kernel ring buffer (dmesg) and auditd telemetry to a centralized data lake for retrospective analysis.
- Track membership changes to the video group, since group membership grants the local access needed to reach the vulnerable code path.
- Baseline expected V4L2 consumers on embedded devices and flag deviations.
How to Mitigate CVE-2026-68219
Immediate Actions Required
- Apply the upstream Linux kernel patches for the imx8-isi driver referenced in the NVD entry.
- Restrict access to /dev/video* nodes on i.MX8 systems to trusted service accounts only.
- Audit which users belong to the video group and remove unnecessary members.
Patch Information
The fix adds a minimum value constraint before applying the downscaling factor to hardware. Upstream stable commits providing the fix include 28ae75d, 57a7ec5c, 690cdda7, 75cdfaa7, and ba7e1b06. Refer to the Linux Kernel Patch 57a7ec5c, Linux Kernel Patch 75cdfaa7, and Linux Kernel Patch ba7e1b06 for backport guidance.
Workarounds
- Unload the imx8-isi kernel module on systems that do not require ISI camera functionality.
- Apply strict filesystem ACLs on /dev/video* to prevent access by unprivileged users until patches are deployed.
- Use a mandatory access control policy (SELinux or AppArmor) to constrain which processes may issue V4L2 ioctls to the ISI device.
# Configuration example: restrict access to ISI device nodes
sudo chown root:video /dev/video0
sudo chmod 0660 /dev/video0
# Optional: disable the driver if unused
echo "blacklist imx8-isi" | sudo tee /etc/modprobe.d/blacklist-imx8-isi.conf
sudo update-initramfs -u
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
