CVE-2022-50095 – A use-after-free vulnerability in the Linux ker... (How to Fix)

Q: What is the severity of CVE-2022-50095?

CVE-2022-50095 has a CVSS score of 7.8 (HIGH). A use-after-free vulnerability in the Linux kernel's posix-cpu-timers subsystem allows local attackers to potentially escalate privileges or cause denial of service. When a non-leader thread executes execve, it fails to properly clean up CPU timers before freeing memory, leading to dangling pointers. This affects Linux systems with vulnerable kernel versions.

📋 TL;DR

A use-after-free vulnerability in the Linux kernel's posix-cpu-timers subsystem allows local attackers to potentially escalate privileges or cause denial of service. When a non-leader thread executes execve, it fails to properly clean up CPU timers before freeing memory, leading to dangling pointers. This affects Linux systems with vulnerable kernel versions.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific vulnerable versions between commit 55e8c8eb2c7b introduction and fix commits listed in references

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires multi-threaded processes with CPU timers. The vulnerability was introduced by a specific commit and fixed in stable kernel branches.

📦 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

Local privilege escalation to root, kernel panic causing system crash, or arbitrary code execution in kernel context.

🟠

Likely Case

Kernel panic leading to denial of service or system instability.

🟢

If Mitigated

Minimal impact if proper access controls prevent local user execution or if systems are patched.

🌐 Internet-Facing: LOW - Requires local access to exploit, not directly reachable via network.

🏢 Internal Only: MEDIUM - Local users or compromised accounts could exploit this for privilege escalation or DoS.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to create multi-threaded processes. Exploitation would need to trigger specific timing conditions.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in stable kernel versions via commits referenced in CVE

Vendor Advisory: https://git.kernel.org/stable/c/541840859ace9c2ccebc32fa9e376c7bd3def490

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. Check kernel version with 'uname -r'. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Restrict local user access

linux

Limit local shell access to trusted users only

Disable unnecessary services

linux

Reduce attack surface by disabling services that allow local code execution

🧯 If You Can't Patch

Implement strict access controls to prevent untrusted local users from executing code
Monitor system logs for kernel panics or unusual process behavior

🔍 How to Verify

Check if Vulnerable:

Check kernel version and compare with distribution's security advisories. Vulnerable if using kernel between introduction of commit 55e8c8eb2c7b and fix commits.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated to patched version from vendor. Check 'uname -r' matches secure version.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
Use-after-free warnings in kernel logs
System crashes or unexpected reboots

Network Indicators:

None - local exploit only

SIEM Query:

source="kernel" AND ("panic" OR "use-after-free" OR "BUG:")

📊 Metadata

CVE ID: CVE-2022-50095

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-416

EPSS Score: 0.02% exploit probability (3.6th percentile)

Published: June 18, 2025

Last Updated: November 18, 2025

🔗 References

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🔗 Related Vulnerabilities

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