CVE-2021-47194 – This CVE describes a Linux kernel vulnerability... (How to Fix)

Q: What is the severity of CVE-2021-47194?

CVE-2021-47194 has a CVSS score of 7.8 (HIGH). This CVE describes a Linux kernel vulnerability in the cfg80211 wireless subsystem where switching from P2P_GO to ADHOC interface type fails to properly clean up resources, leading to memory corruption. This affects Linux systems using wireless networking with P2P_GO functionality. Attackers could potentially exploit this to cause denial of service or execute arbitrary code.

📋 TL;DR

This CVE describes a Linux kernel vulnerability in the cfg80211 wireless subsystem where switching from P2P_GO to ADHOC interface type fails to properly clean up resources, leading to memory corruption. This affects Linux systems using wireless networking with P2P_GO functionality. Attackers could potentially exploit this to cause denial of service or execute arbitrary code.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not explicitly stated in CVE, but patches available for multiple stable branches

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Requires wireless networking with P2P_GO functionality enabled and userspace tools capable of switching interface types.

📦 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 →

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 memory corruption leading to system crash, denial of service, or potential arbitrary code execution with kernel privileges.

🟠

Likely Case

System instability, kernel panic, or denial of service affecting wireless functionality.

🟢

If Mitigated

Limited impact if wireless interfaces are properly configured and monitored, with potential for service disruption only.

🌐 Internet-Facing: LOW - Requires local access to wireless interface configuration.

🏢 Internal Only: MEDIUM - Could be exploited by users with wireless configuration privileges on affected systems.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires ability to modify wireless interface configuration, typically requiring local access or specific wireless management privileges.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with fixes (see git commits in references)

Vendor Advisory: https://git.kernel.org/stable/c/563fbefed46ae4c1f70cffb8eb54c02df480b2c2

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable P2P_GO functionality

linux

Prevent switching to P2P_GO interface type if not required

# Configuration depends on wireless management tools used

Restrict wireless interface configuration

linux

Limit userspace tools that can modify wireless interface types

# Use appropriate access controls (SELinux, AppArmor, permissions)

🧯 If You Can't Patch

Restrict wireless configuration capabilities to trusted users only
Monitor for unusual wireless interface type changes or system instability

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if wireless subsystem with P2P_GO is enabled

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated to include the git commits referenced in the CVE

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs
Wireless subsystem errors
System instability after interface changes

Network Indicators:

Unexpected wireless interface behavior
Network service disruption

SIEM Query:

Search for kernel panic events or wireless configuration changes followed by system instability

📊 Metadata

CVE ID: CVE-2021-47194

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-665

Published: April 10, 2024

Last Updated: November 21, 2024

🔗 References

📤 Share & Export

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🔗 Related Vulnerabilities

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