CVE-2023-0615: Linux Kernel V4L2 DOS Vulnerability

CVE-2023-0615 Overview

CVE-2023-0615 is a vulnerability in the Linux kernel's Video4Linux2 (V4L2) subsystem, specifically in the vivid virtual video test driver. The flaw combines a memory leak, a potential divide-by-zero, and an integer overflow that can be triggered through ioctl calls such as VIDIOC_S_DV_TIMINGS. A local authenticated user can exploit the issue to crash the system when the vivid test driver is enabled. The vulnerability affects Linux kernel 6.2 release candidates and is tracked under [CWE-20] (Improper Input Validation) and [CWE-190] (Integer Overflow).

Critical Impact
Local users with low privileges can trigger a denial-of-service condition on systems running the affected kernel with vivid enabled, with an EPSS probability of 0.016%.

Affected Products

Linux kernel 6.2-rc1 through 6.2-rc5
Linux distributions shipping the vivid V4L2 test module
Systems with V4L2 subsystem enabled and accessible to local users

Discovery Timeline

2023-02-06 - CVE-2023-0615 published to NVD
2025-03-25 - Last updated in NVD database

Technical Details for CVE-2023-0615

Vulnerability Analysis

The vulnerability resides in the vivid driver, a virtual video device used for testing the V4L2 framework. The flaw exposes three distinct weaknesses: a memory leak, a divide-by-zero condition, and an integer overflow. All three are reachable through user-space ioctl interfaces exposed by the /dev/video* character devices created by the driver.

The VIDIOC_S_DV_TIMINGS ioctl is the primary trigger. This ioctl accepts digital video timing parameters from user space. Without proper validation, attacker-controlled values flow into arithmetic operations and resource allocations within the kernel.

Successful exploitation results in kernel panic or resource exhaustion, producing a denial-of-service condition. The issue does not provide memory disclosure or code execution paths according to the CVSS impact metrics.

Root Cause

The root cause is missing or insufficient validation of user-supplied timing parameters before they are used in calculations. Specific values trigger division operations where the divisor evaluates to zero, while large values cause integer overflow during arithmetic on timing fields. The memory leak component stems from allocation paths that do not release resources on error returns.

Attack Vector

Exploitation requires local access and the ability to open the vivid device node. An attacker invokes VIDIOC_S_DV_TIMINGS with crafted timing structures whose fields force divide-by-zero or overflow conditions. The exploit path is contained entirely within ioctl handling and does not require additional capabilities beyond device file access. See the Red Hat Bug Report #2166287 for technical details on the affected code paths.

Detection Methods for CVE-2023-0615

Indicators of Compromise

Unexpected kernel panics or oops messages referencing vivid or v4l2 symbols in dmesg
Growing unaccounted kernel slab memory on hosts running the vivid module
Repeated ioctl calls against /dev/video* nodes from non-administrative user accounts

Detection Strategies

Inspect loaded kernel modules with lsmod | grep vivid to identify systems exposing the vulnerable driver
Audit access control lists on /dev/video* devices to enumerate which local users can reach the vulnerable ioctl surface
Correlate kernel crash dumps with V4L2 stack frames to identify attempted exploitation

Monitoring Recommendations

Forward kernel log events to a centralized logging platform and alert on panics that include vivid_ or v4l2_ symbols
Monitor auditd for ioctl syscalls targeting V4L2 device nodes from unexpected user contexts
Track unplanned reboots on Linux hosts running pre-release 6.2 kernels

How to Mitigate CVE-2023-0615

Immediate Actions Required

Unload the vivid module on production systems where it is not required using modprobe -r vivid
Blacklist the vivid module to prevent automatic loading at boot
Restrict permissions on /dev/video* device nodes to trusted users and groups only
Update affected systems to a stable Linux kernel release that includes upstream fixes for the V4L2 timing validation paths

Patch Information

The vulnerability affects Linux kernel 6.2 release candidates (rc1 through rc5). Refer to the Red Hat Bug Report #2166287 for upstream patch references and distribution-specific fixes. Apply vendor-supplied kernel updates that include validation for VIDIOC_S_DV_TIMINGS parameters.

Workarounds

Disable the CONFIG_VIDEO_VIVID kernel option when building custom kernels for production workloads
Add blacklist vivid to /etc/modprobe.d/blacklist.conf to prevent the module from loading
Apply mandatory access control policies (SELinux or AppArmor) to limit which processes can issue ioctls against V4L2 device nodes

bash

# Configuration example
# Prevent the vivid test module from loading at boot
echo "blacklist vivid" | sudo tee /etc/modprobe.d/disable-vivid.conf
sudo modprobe -r vivid

# Verify the module is no longer loaded
lsmod | grep vivid