Listen to this Post
– How CVE-2026-46205 Works
CVE-2026-46205 resides in the `atomisp` driver, a component of the Linux kernel’s `staging: media` subsystem that provides support for Intel’s Atom Image Signal Processor (ISP). The driver implements private IOCTL handlers—custom, device‑specific control operations accessible from user space via the `/dev/video` device node.
In the vulnerable code, the function `atomisp_vidioc_default()` processes IOCTL commands without adequate security validation. Specifically, when a user‑space application passes a non‑zero `cmd` value, the driver proceeds to execute the corresponding private IOCTL handler. These handlers were originally designed for testing or debugging purposes and were never intended to be exposed to untrusted user space.
Because private IOCTLs are not subjected to the same rigorous safety checks as standard V4L2 IOCTLs, an attacker with local access can craft a malicious IOCTL request that triggers undefined behaviour in the kernel. The lack of proper input validation and permission checks means that a successful exploit could lead to:
– Information disclosure – reading sensitive kernel memory.
– Denial of service – crashing the kernel via a malformed request.
– Local privilege escalation – manipulating kernel structures to gain root privileges.
The Linux kernel CVE team assigned a CVSS v3.1 base score of 7.8 (HIGH) with the vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, reflecting the ease of exploitation and the severe impact on system integrity, confidentiality, and availability.
The fix adopted by the kernel developers is to disallow all private IOCTLs entirely. Instead of removing the code (which would break static analysis checks), the patch modifies `atomisp_vidioc_default()` to return immediately if `cmd` is non‑zero. This approach effectively neuters all private IOCTL handlers without altering the rest of the driver logic.
The vulnerability has been present since Linux kernel version 4.12 and is fixed in later stable releases (e.g., 6.6.140, 6.12.90, 6.18.32, 7.0.9, and 7.1‑rc1). Users running any kernel between 4.12 and the fixed versions are at risk if the `atomisp` driver is loaded (i.e., on systems with Intel Atom ISP hardware).
DailyCVE Form
Platform: ……. Linux Kernel
Version: …….. 4.12 → fixed
Vulnerability :.. Private IOCTL Disallow
Severity: ……. HIGH (7.8)
Date: ……….. 2026‑05‑28
Prediction: ….. 2026‑06‑10
What Undercode Say
Analytics
- Attack Complexity: Low – local access only, no special privileges required.
- User Interaction: None – can be exploited without user action.
- Privileges Required: Low – any local user can invoke the driver.
- Impact: Full confidentiality, integrity, and availability compromise.
Bash Commands to Check Vulnerability
Check your current kernel version uname -r List loaded modules and grep for atomisp lsmod | grep atomisp If the module is loaded and kernel version is between 4.12 and the fixed releases, you are vulnerable. Example of checking if a specific vulnerable version is running: if [[ "$(uname -r)" =~ ^4.12 ]]; then echo "VULNERABLE: kernel 4.12 is affected" fi
Code Snippet – The Vulnerable Function
// drivers/staging/media/atomisp/pci/atomisp_ioctl.c
static long atomisp_vidioc_default(struct file file, void fh, bool valid_prio,
unsigned int cmd, void arg)
{
// ... original code would process private IOCTLs when cmd != 0
// ... leading to unsafe operations
}
Code Snippet – The Patch
static long atomisp_vidioc_default(struct file file, void fh, bool valid_prio,
unsigned int cmd, void arg)
{
// Disallow all private IOCTLs
if (cmd != 0)
return -ENOTTY;
// ... remaining safe V4L2 IOCTL handling
}
Exploit
An attacker can trigger the vulnerability by opening the `/dev/video` device node associated with the `atomisp` driver and invoking a private IOCTL with a custom `cmd` value. For example:
include <sys/ioctl.h>
include <fcntl.h>
int main() {
int fd = open("/dev/video0", O_RDWR);
if (fd < 0) return 1;
// Trigger a private IOCTL (any non-zero cmd)
ioctl(fd, 0xdeadbeef, NULL);
close(fd);
return 0;
}
Because the vulnerable handler performs insufficient checks, this could lead to kernel oops, memory corruption, or privilege escalation depending on the hardware and kernel configuration. No public proof‑of‑concept has been released, but the simplicity of the attack surface makes exploitation highly plausible.
Protection
- Update the Linux kernel to one of the fixed versions:
– 6.6.140 or later
– 6.12.90 or later
– 6.18.32 or later
– 7.0.9 or later
– 7.1-rc1 or later
2. If an immediate update is impossible, blacklist the `atomisp` module:
echo "blacklist atomisp" >> /etc/modprobe.d/blacklist.conf reboot
3. Apply the minimal patch if building a custom kernel:
Add the `if (cmd != 0) return -ENOTTY;` check at the beginning of atomisp_vidioc_default().
4. Restrict local access to trusted users only, as the attack requires local unprivileged access.
Impact
- System compromise – Any local user can potentially gain full root control over the system.
- Information leakage – Sensitive kernel data (e.g., cryptographic keys, memory contents) could be exposed.
- Denial of service – Malicious IOCTL requests can crash the kernel, leading to system unavailability.
- Widespread exposure – The `atomisp` driver is present in all Linux distributions that ship kernel 4.12 or later and support Intel Atom ISP hardware (e.g., certain tablets, embedded devices, and laptops).
> Note: This vulnerability does not require any network access; it is purely local. However, on multi‑user systems or cloud environments where local access is possible, it poses a critical risk.
🎯Let’s Practice Exploiting & Learn Patching For Free:
🎓 Live Courses & Certifications:
Join Undercode Academy for Verified Certifications
🚀 Request a Custom Project:
Secure, high-velocity infrastructure and disruptive technological engineering. Contact our engineering team for high-tier development and proprietary systems:
[email protected]
💎 Smart Architecture | 🛡️ Secure by Design | ⭐ Trusted by Thousands
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
