CVE-2024-35969 – A race condition in the Linux kernel's IPv6 imp... (How to Fix)

Q: What is the severity of CVE-2024-35969?

CVE-2024-35969 has a CVSS score of 5.5 (MEDIUM). A race condition in the Linux kernel's IPv6 implementation allows a use-after-free vulnerability when ipv6_get_ifaddr and ipv6_del_addr execute concurrently. This can lead to kernel memory corruption and potential system crashes. Systems running vulnerable Linux kernel versions with IPv6 enabled are affected.

📋 TL;DR

A race condition in the Linux kernel's IPv6 implementation allows a use-after-free vulnerability when ipv6_get_ifaddr and ipv6_del_addr execute concurrently. This can lead to kernel memory corruption and potential system crashes. Systems running vulnerable Linux kernel versions with IPv6 enabled are affected.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific versions between initial introduction and fix commit 01b11a0566670612bd464a932e5ac2eae53d8652

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires IPv6 to be enabled and network operations that trigger the specific race condition.

📦 What is this software?

Debian Linux by Debian

View all CVEs affecting Debian Linux →

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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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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash, denial of service, or potential privilege escalation if combined with other vulnerabilities.

🟠

Likely Case

System instability, kernel crashes, or denial of service affecting network functionality.

🟢

If Mitigated

Minor performance impact or no noticeable effect if race condition doesn't trigger.

🌐 Internet-Facing: MEDIUM - Requires network access and specific timing conditions to trigger.

🏢 Internal Only: MEDIUM - Internal attackers could potentially trigger the race condition.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Exploitation requires precise timing to trigger the race condition and may be difficult to reliably reproduce.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions with commit 01b11a0566670612bd464a932e5ac2eae53d8652 or later

Vendor Advisory: https://git.kernel.org/stable/c/01b11a0566670612bd464a932e5ac2eae53d8652

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable IPv6

linux

Temporarily disable IPv6 to prevent the race condition from being triggered.

echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
echo 1 > /proc/sys/net/ipv6/conf/default/disable_ipv6

🧯 If You Can't Patch

Implement network segmentation to limit exposure
Monitor systems for kernel crashes or instability

🔍 How to Verify

Check if Vulnerable:

Check kernel version and verify if it includes the vulnerable code before the fix commit.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes commit 01b11a0566670612bd464a932e5ac2eae53d8652 or check with distribution's security update status.

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs
refcount_t warnings in dmesg
system crash reports

Network Indicators:

Unexpected network interface failures
IPv6 address assignment issues

SIEM Query:

source="kernel" AND ("refcount_t" OR "use-after-free" OR "ipv6_get_ifaddr")

📊 Metadata

CVE ID: CVE-2024-35969

CVSS v3 Score: 5.5 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-770

Published: May 20, 2024

Last Updated: April 4, 2025

🔗 References

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🔗 Related Vulnerabilities

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