CVE-2026-68230: Linux Kernel Buffer Overflow Vulnerability

CVE-2026-68230 Overview

CVE-2026-68230 is a Linux kernel vulnerability in the Amlogic C3 Image Signal Processor (ISP) media driver. The flaw resides in the auto-exposure (AE) and auto-white-balance (AWB) configuration handling within drivers/media/platform/amlogic/c3/isp/c3-isp-params.c. The driver fails to validate that the user-supplied zones_num value does not exceed the size of the zone_weight array, allowing an out-of-bounds write into kernel memory. A local authenticated attacker with access to the ISP parameters interface can trigger invalid memory access, leading to kernel memory corruption or denial of service.

Critical Impact
A local attacker can trigger a kernel buffer overflow through the Amlogic C3 ISP parameters interface, resulting in memory corruption and potential system instability.

Affected Products

Linux kernel with the amlogic-c3 ISP media driver enabled
drivers/media/platform/amlogic/c3/isp/c3-isp-params.c in affected kernel branches
Devices using Amlogic C3 SoC media/camera subsystems

Discovery Timeline

2026-08-10 - CVE-2026-68230 published to NVD
2026-08-13 - Last updated in NVD database

Technical Details for CVE-2026-68230

Vulnerability Analysis

The vulnerability affects the Amlogic C3 ISP media driver, which exposes AE and AWB configuration to userspace through V4L2 controls. Two functions are affected: c3_isp_params_awb_wt() at line 111 and c3_isp_params_ae_wt() at line 227. Both functions iterate up to zones_num entries when writing into the fixed-size zone_weight array.

The zone_weight buffer holds 768 entries for AWB and 255 entries for AE. Because zones_num is a u32 value supplied through the configuration structure, it can reach u32max without bounds checking. Static analysis via smatch flagged both write paths as buffer overflows. The fix adds explicit validation ensuring zones_num does not exceed the size of zone_weight before iteration begins.

Root Cause

The root cause is missing input validation on the zones_num field within the AE and AWB configuration structures. The driver trusted the caller-provided count without comparing it against the destination array size, creating an out-of-bounds write [CWE-787] condition.

Attack Vector

Exploitation requires local access with permissions to open the C3 ISP V4L2 device node and submit configuration parameters. An attacker crafts a configuration payload with a zones_num value larger than the zone_weight array length. Submitting this payload causes the kernel driver to write beyond the buffer boundary in kernel memory. See the upstream fix commit for the corrected validation logic.

Detection Methods for CVE-2026-68230

Indicators of Compromise

Unexpected kernel oops, panic, or KASAN reports referencing c3_isp_params_awb_wt or c3_isp_params_ae_wt
Kernel log entries showing slab-out-of-bounds writes in drivers/media/platform/amlogic/c3/isp/
Unprivileged processes opening /dev/video* nodes bound to the C3 ISP subdevice

Detection Strategies

Enable KASAN on test kernels to catch out-of-bounds writes in the C3 ISP parameter handlers
Audit installed kernel versions on Amlogic C3-based devices against the fixed commits
Monitor dmesg and syslog for media pipeline crashes correlated with V4L2 ioctl activity

Monitoring Recommendations

Forward kernel logs from Amlogic C3 devices to a centralized log platform for anomaly review
Alert on repeated V4L2 VIDIOC_S_EXT_CTRLS calls from non-camera userspace processes
Track kernel version inventory to identify unpatched devices exposed to local users

How to Mitigate CVE-2026-68230

Immediate Actions Required

Apply the upstream kernel patches that add validation of zones_num against zone_weight size
Restrict access to /dev/video* nodes associated with the C3 ISP to trusted camera services only
Rebuild and deploy vendor kernels for Amlogic C3-based devices using the fixed source

Patch Information

The fix is upstream in stable Linux kernel trees. Refer to the primary fix commit, the backport commit, and the additional stable backport. The patch introduces explicit checks that reject configurations where zones_num exceeds the fixed zone_weight array capacity of 768 (AWB) or 255 (AE).

Workarounds

Disable the amlogic-c3 ISP module (CONFIG_VIDEO_C3_MIPI_ISP) on kernels where patching is not immediately feasible
Apply Unix DAC or SELinux/AppArmor policy to restrict the C3 ISP device node to a dedicated camera service account
Remove or blacklist the c3-isp kernel module on devices that do not require camera functionality

bash

# Example: blacklist the c3-isp module until the kernel is patched
echo 'blacklist c3-isp' | sudo tee /etc/modprobe.d/blacklist-c3-isp.conf
sudo depmod -a
sudo update-initramfs -u