CVE-2021-4083
📋 TL;DR
A race condition vulnerability in the Linux kernel's Unix domain socket garbage collection allows local users to trigger a read-after-free memory flaw. This can lead to system crashes or privilege escalation. Affects Linux kernel versions prior to 5.16-rc4.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Communications Cloud Native Core Binding Support Function by Oracle
View all CVEs affecting Communications Cloud Native Core Binding Support Function →
Communications Cloud Native Core Network Exposure Function by Oracle
View all CVEs affecting Communications Cloud Native Core Network Exposure Function →
Communications Cloud Native Core Policy by Oracle
View all CVEs affecting Communications Cloud Native Core Policy →
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 →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 →Solidfire by Netapp
⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to root, complete system compromise
Likely Case
Local denial of service (system crash/kernel panic)
If Mitigated
No impact if patched or proper access controls prevent local user execution
🎯 Exploit Status
Exploit requires local access and race condition timing, but proof-of-concept code exists in public advisories
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 5.16-rc4 and later
Vendor Advisory: https://bugzilla.redhat.com/show_bug.cgi?id=2029923
Restart Required: Yes
Instructions:
1. Update Linux kernel to version 5.16-rc4 or later
2. Apply vendor-specific kernel patches for your distribution
3. Reboot the system to load the new kernel
🔧 Temporary Workarounds
Restrict local user access
linuxLimit local shell access to trusted users only
🧯 If You Can't Patch
- Implement strict access controls to prevent untrusted local users from executing code
- Monitor for kernel panic/crash events and investigate suspicious local user activity
🔍 How to Verify
Check if Vulnerable:
Check kernel version: uname -r and compare to 5.16-rc4Check Version:
uname -rVerify Fix Applied:
Verify kernel version is 5.16-rc4 or later: uname -r📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- System crash/reboot events
- Suspicious local user privilege escalation
Network Indicators:
- None - local exploit only
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "general protection fault")🔗 References
- https://bugzilla.redhat.com/show_bug.cgi?id=2029923
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=054aa8d439b9
- https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://security.netapp.com/advisory/ntap-20220217-0005/
- https://www.debian.org/security/2022/dsa-5096
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://bugzilla.redhat.com/show_bug.cgi?id=2029923
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=054aa8d439b9
- https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://security.netapp.com/advisory/ntap-20220217-0005/
- https://www.debian.org/security/2022/dsa-5096
- https://www.oracle.com/security-alerts/cpujul2022.html
