CVE-2022-48649 – A double-free vulnerability in the Linux kernel... (How to Fix)

Q: What is the severity of CVE-2022-48649?

CVE-2022-48649 has a CVSS score of 7.8 (HIGH). A double-free vulnerability in the Linux kernel's memory management subsystem allows attackers to cause a use-after-free condition when destroying kmem_cache objects. This can lead to kernel memory corruption, system crashes, or potential privilege escalation. All Linux systems running vulnerable kernel versions are affected.

📋 TL;DR

A double-free vulnerability in the Linux kernel's memory management subsystem allows attackers to cause a use-after-free condition when destroying kmem_cache objects. This can lead to kernel memory corruption, system crashes, or potential privilege escalation. All Linux systems running vulnerable kernel versions are affected.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific vulnerable versions not explicitly stated, but affects kernels before fixes in commits c673c6ceac53fb2e631c9fbbd79957099a08927f and d71608a877362becdc94191f190902fac1e64d35

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires slub_debug testing or similar conditions to trigger, but could be exploited through crafted operations.

📦 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...

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash, potential privilege escalation to root, or arbitrary code execution in kernel context.

🟠

Likely Case

System instability, kernel crashes, denial of service, or memory corruption affecting system reliability.

🟢

If Mitigated

Limited impact if proper kernel hardening and isolation are in place, but still risks system stability.

🌐 Internet-Facing: LOW - Requires local access or ability to trigger specific kernel operations.

🏢 Internal Only: MEDIUM - Local attackers or malicious processes could exploit this to crash systems or escalate privileges.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH - Requires specific timing conditions and kernel memory manipulation.

Exploitation requires local access and ability to trigger kmem_cache operations with specific timing.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits c673c6ceac53fb2e631c9fbbd79957099a08927f and d71608a877362becdc94191f190902fac1e64d35

Vendor Advisory: https://git.kernel.org/stable/c/c673c6ceac53fb2e631c9fbbd79957099a08927f

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.

🔧 Temporary Workarounds

Disable slub_debug

linux

Prevents triggering the vulnerability through slub_debug testing scenarios

echo 0 > /sys/kernel/slab/kmem_cache/slub_debug
Remove 'slub_debug' from kernel boot parameters

🧯 If You Can't Patch

Restrict local user access and limit process capabilities
Implement kernel hardening features like SELinux/AppArmor to contain potential damage

🔍 How to Verify

Check if Vulnerable:

Check kernel version and compare with patched releases containing the fix commits

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits: c673c6ceac53fb2e631c9fbbd79957099a08927f and d71608a877362becdc94191f190902fac1e64d35

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
KASAN use-after-free reports
slab corruption warnings in dmesg

Network Indicators:

None - local vulnerability only

SIEM Query:

source="kernel" AND ("KASAN" OR "use-after-free" OR "slab corruption")

📊 Metadata

CVE ID: CVE-2022-48649

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-415

Published: April 28, 2024

Last Updated: January 10, 2025

🔗 References

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