CVE-2024-35952 – A race condition in the Linux kernel's AST DRM ... (How to Fix)

Q: What is the severity of CVE-2024-35952?

CVE-2024-35952 has a CVSS score of 5.5 (MEDIUM). A race condition in the Linux kernel's AST DRM driver causes a soft lockup when the driver waits indefinitely for a BMC microcontroller to update scratch registers. This affects systems using AST graphics hardware with BMC management controllers, potentially causing system hangs.

📋 TL;DR

A race condition in the Linux kernel's AST DRM driver causes a soft lockup when the driver waits indefinitely for a BMC microcontroller to update scratch registers. This affects systems using AST graphics hardware with BMC management controllers, potentially causing system hangs.

💻 Affected Systems

Products:

Linux kernel with AST DRM driver

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

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires AST graphics hardware with BMC management controller. Most consumer systems are unaffected; primarily affects servers/workstations with AST graphics.

📦 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

Complete system lockup requiring hard reboot, leading to denial of service and potential data loss or corruption.

🟠

Likely Case

Temporary system hangs or performance degradation during display operations, particularly when using DP (DisplayPort) connections.

🟢

If Mitigated

Minor performance impact during display initialization with proper kernel patches applied.

🌐 Internet-Facing: LOW - Requires local access to the affected system's graphics subsystem.

🏢 Internal Only: MEDIUM - Could affect workstation stability and availability in environments using AST graphics hardware.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires triggering the race condition through display operations. No known public exploits exist.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Linux kernel with commits 35768baf0fdfc47ede42d899506bad78450e9294 and related fixes

Vendor Advisory: https://git.kernel.org/stable/c/35768baf0fdfc47ede42d899506bad78450e9294

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable AST graphics if not needed

linux

Blacklist AST DRM module to prevent loading

echo 'blacklist ast' >> /etc/modprobe.d/blacklist.conf
update-initramfs -u
reboot

🧯 If You Can't Patch

Avoid using DisplayPort connections on affected AST hardware
Monitor system for soft lockups and implement automated recovery procedures

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if AST module is loaded: lsmod | grep ast && uname -r

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits or is newer than vulnerable versions

📡 Detection & Monitoring

Log Indicators:

Kernel soft lockup messages in dmesg
'BUG: soft lockup' in system logs
High CPU usage by kernel threads

Network Indicators:

None - local vulnerability only

SIEM Query:

source="kernel" AND "soft lockup" AND "CPU"

📊 Metadata

CVE ID: CVE-2024-35952

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-667

Published: May 20, 2024

Last Updated: September 23, 2025

🔗 References

📤 Share & Export

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🔗 Related Vulnerabilities

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