CVE-2021-46943 – A vulnerability in the Linux kernel's Intel IPU... (How to Fix)

Q: What is the severity of CVE-2021-46943?

CVE-2021-46943 has a CVSS score of 7.8 (HIGH). A vulnerability in the Linux kernel's Intel IPU3 media driver allows attackers to cause a denial-of-service (system crash) or potentially execute arbitrary code. The flaw occurs when error handling during format setting fails to properly validate configurations, leading to memory corruption. This affects systems using the Intel IPU3 image processing unit with vulnerable kernel versions.

📋 TL;DR

A vulnerability in the Linux kernel's Intel IPU3 media driver allows attackers to cause a denial-of-service (system crash) or potentially execute arbitrary code. The flaw occurs when error handling during format setting fails to properly validate configurations, leading to memory corruption. This affects systems using the Intel IPU3 image processing unit with vulnerable kernel versions.

💻 Affected Systems

Products:

Linux kernel with Intel IPU3 driver

Versions: Kernel versions before the fix commits (specific versions vary by distribution)

Operating Systems: Linux distributions with vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with Intel IPU3 hardware and the staging/intel-ipu3 driver loaded.

📦 What is this software?

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash, or potential arbitrary code execution with kernel privileges resulting in complete system compromise.

🟠

Likely Case

Denial-of-service through kernel panic or system crash when malformed media format requests are processed.

🟢

If Mitigated

Limited impact if system has proper access controls and doesn't process untrusted media input.

🌐 Internet-Facing: LOW - Requires local access or ability to submit media processing requests.

🏢 Internal Only: MEDIUM - Could be exploited by local users or through applications that use the IPU3 driver.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires ability to trigger set_fmt operations on the IPU3 driver, typically requiring local access or application-level access.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits 34892ea938387d83ffcfb7775ec55f0f80767916 or related fixes

Vendor Advisory: https://git.kernel.org/stable/c/34892ea938387d83ffcfb7775ec55f0f80767916

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel. 3. Reboot system to load patched kernel.

🔧 Temporary Workarounds

Disable IPU3 driver

linux

Prevent loading of the vulnerable driver module

echo 'blacklist ipu3-imgu' >> /etc/modprobe.d/blacklist.conf
rmmod ipu3-imgu

Restrict device access

linux

Limit access to the IPU3 device file

chmod 600 /dev/video*
setfacl -m u:root:rw /dev/video*

🧯 If You Can't Patch

Restrict local user access to systems with IPU3 hardware
Implement strict application sandboxing for media processing applications

🔍 How to Verify

Check if Vulnerable:

Check if IPU3 driver is loaded: lsmod | grep ipu3-imgu AND check kernel version against patched versions

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and IPU3 driver functions without crashes during format operations

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
'general protection fault' errors
'swiotlb buffer is full' warnings
OOM killer activity

Network Indicators:

None - local vulnerability

SIEM Query:

source="kernel" AND ("general protection fault" OR "ipu3-imgu" OR "swiotlb buffer is full")

📊 Metadata

CVE ID: CVE-2021-46943

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-131

Published: February 27, 2024

Last Updated: November 21, 2024

🔗 References

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🔗 Related Vulnerabilities

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