CVE-2024-44934 – A use-after-free vulnerability in the Linux ker... (How to Fix)

Q: What is the severity of CVE-2024-44934?

CVE-2024-44934 has a CVSS score of 7.8 (HIGH). A use-after-free vulnerability in the Linux kernel's bridge multicast implementation allows an attacker to potentially crash the system or execute arbitrary code. This affects systems using bridge networking with multicast enabled. The vulnerability occurs when a port is removed while garbage collection timers are still running.

📋 TL;DR

A use-after-free vulnerability in the Linux kernel's bridge multicast implementation allows an attacker to potentially crash the system or execute arbitrary code. This affects systems using bridge networking with multicast enabled. The vulnerability occurs when a port is removed while garbage collection timers are still running.

💻 Affected Systems

Products:

Linux kernel

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

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when bridge networking with multicast is enabled. Most default configurations do not have bridge networking enabled.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic, system crash, or potential arbitrary code execution with kernel privileges leading to complete system compromise.

🟠

Likely Case

System crash or kernel panic causing denial of service on affected systems.

🟢

If Mitigated

Limited impact if bridge networking and multicast are disabled or if systems are patched.

🌐 Internet-Facing: MEDIUM - Requires bridge networking with multicast enabled, which is less common on internet-facing systems.

🏢 Internal Only: MEDIUM - Bridge networking with multicast is more common in internal virtualization/container environments.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires local access and specific conditions (bridge networking with multicast). The race condition makes reliable exploitation challenging.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 0d8b26e10e680c01522d7cc14abe04c3265a928f, 1e16828020c674b3be85f52685e8b80f9008f50f, 92c4ee25208d0f35dafc3213cdf355fbe449e078, b2f794b168cf560682ff976b255aa6d29d14a658, e3145ca904fa8dbfd1a5bf0187905bc117b0efce

Vendor Advisory: https://git.kernel.org/stable/c/0d8b26e10e680c01522d7cc14abe04c3265a928f

Restart Required: Yes

Instructions:

1. Update Linux kernel to 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 bridge multicast

linux

Disable multicast on bridge interfaces to prevent the vulnerable code path

echo 0 > /sys/class/net/br0/bridge/multicast_snooping
ip link set dev br0 type bridge mcast_snooping 0

Remove bridge interfaces

linux

Remove bridge networking if not required

ip link delete br0
brctl delbr br0

🧯 If You Can't Patch

Disable bridge networking entirely if not required
Ensure no bridge interfaces have multicast enabled

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if bridge interfaces exist with multicast enabled: 'uname -r' and 'ip link show type bridge'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is patched and check for bridge interfaces: 'cat /sys/class/net/br0/bridge/multicast_snooping' should show 0 if disabled

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
KASAN use-after-free reports in dmesg
Bridge interface removal errors

Network Indicators:

Unexpected bridge interface disappearance
Multicast traffic disruption

SIEM Query:

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

📊 Metadata

CVE ID: CVE-2024-44934

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

Published: August 26, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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