CVE-2022-48847 – This is an out-of-bounds write vulnerability in... (How to Fix)

Q: What is the severity of CVE-2022-48847?

CVE-2022-48847 has a CVSS score of 7.8 (HIGH). This is an out-of-bounds write vulnerability in the Linux kernel's watch_queue subsystem due to improper bounds checking. Attackers with local access can trigger kernel memory corruption, potentially leading to privilege escalation or denial of service. All Linux systems using affected kernel versions are vulnerable.

📋 TL;DR

This is an out-of-bounds write vulnerability in the Linux kernel's watch_queue subsystem due to improper bounds checking. Attackers with local access can trigger kernel memory corruption, potentially leading to privilege escalation or denial of service. All Linux systems using affected kernel versions are vulnerable.

💻 Affected Systems

Products:

Linux Kernel

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

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires CONFIG_WATCH_QUEUE=y kernel configuration, which is enabled in many distributions. Users need CAP_SYS_ADMIN or appropriate permissions to trigger the vulnerable ioctl.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Local privilege escalation to root, complete system compromise, or persistent denial of service through kernel panic.

🟠

Likely Case

Kernel crash/panic causing system instability or denial of service, potentially requiring reboot.

🟢

If Mitigated

Limited to denial of service if exploit attempts are detected and blocked by security controls.

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

🏢 Internal Only: HIGH - Local users or compromised accounts can exploit this for privilege escalation.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to call the vulnerable ioctl. The KASAN report shows clear exploitation path but requires kernel knowledge to weaponize.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 1b09f28f70a5046acd64138075ae3f095238b045, 648895da69ced90ca770fd941c3d9479a9d72c16, b36588ebbcef74583824c08352e75838d6fb4ff2, c993ee0f9f81caf5767a50d1faeba39a0dc82af2

Vendor Advisory: https://git.kernel.org/stable/c/1b09f28f70a5046acd64138075ae3f095238b045

Restart Required: Yes

Instructions:

1. Update to a kernel version containing the fix commits. 2. Check your distribution's security advisories for specific patched versions. 3. Reboot the system after kernel update.

🔧 Temporary Workarounds

Disable watch_queue module

linux

Remove or blacklist the watch_queue functionality if not needed

echo "blacklist watch_queue" >> /etc/modprobe.d/blacklist.conf
update-initramfs -u

Restrict ioctl access

linux

Use SELinux/AppArmor to restrict access to the vulnerable ioctl calls

🧯 If You Can't Patch

Implement strict access controls to limit local user privileges
Monitor for kernel panic/crash events and investigate suspicious local user activity

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if watch_queue is enabled: uname -r && grep CONFIG_WATCH_QUEUE /boot/config-$(uname -r)

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is patched by checking if it includes the fix commits: git log --oneline | grep -E '1b09f28f70a5|648895da69ce|b36588ebbcef|c993ee0f9f81'

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
KASAN reports for slab-out-of-bounds writes
Watch queue related errors in dmesg

Network Indicators:

None - local exploit only

SIEM Query:

source="kernel" AND ("KASAN" OR "slab-out-of-bounds" OR "watch_queue")

📊 Metadata

CVE ID: CVE-2022-48847

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-787

Published: July 16, 2024

Last Updated: November 21, 2024

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2022-48847, you might also want to check these: