CVE-2024-40945 – A Linux kernel vulnerability in the iommu_sva

Q: What is the severity of CVE-2024-40945?

CVE-2024-40945 has a CVSS score of 5.5 (MEDIUM). A Linux kernel vulnerability in the iommu_sva_bind_device() function could potentially cause a kernel NULL pointer dereference if the function returns NULL instead of an error pointer. This affects systems using IOMMU SVA features with specific drivers (idxd and uacce). The vulnerability requires local access and specific kernel configurations to be exploitable.

📋 TL;DR

A Linux kernel vulnerability in the iommu_sva_bind_device() function could potentially cause a kernel NULL pointer dereference if the function returns NULL instead of an error pointer. This affects systems using IOMMU SVA features with specific drivers (idxd and uacce). The vulnerability requires local access and specific kernel configurations to be exploitable.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific versions between initial introduction of affected code and patched versions (check git commits for exact range)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when CONFIG_IOMMU_SVA is enabled and using idxd or uacce drivers. Most systems don't have this enabled by default.

📦 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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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 and denial of service, potentially allowing local privilege escalation if combined with other vulnerabilities.

🟠

Likely Case

System crash or instability when using affected IOMMU SVA features with idxd or uacce drivers in specific configurations.

🟢

If Mitigated

No impact if CONFIG_IOMMU_SVA is not enabled or affected drivers are not used.

🌐 Internet-Facing: LOW - Requires local access and specific kernel configuration.

🏢 Internal Only: MEDIUM - Could affect servers using IOMMU SVA features with vulnerable drivers.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: HIGH

Requires local access, specific kernel configuration, and use of affected drivers. Theoretical vulnerability that hasn't been observed in practice.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patched in kernel commits: 2973b8e7d127754de9013177c41c0b5547406998, 61a96da9649a6b6a1a5d5bde9374b045fdb5c12e, 6325eab6c108fed27f60ff51852e3eac0ba23f3f, 700f564758882db7c039dfba9443fe762561a3f8, 7388ae6f26c0ba95f70cc96bf9c5d5cb06c908b6

Vendor Advisory: https://git.kernel.org/stable/c/2973b8e7d127754de9013177c41c0b5547406998

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.

🔧 Temporary Workarounds

Disable IOMMU SVA support

linux

Disable CONFIG_IOMMU_SVA kernel configuration to prevent vulnerable code path

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

🧯 If You Can't Patch

Disable idxd and uacce drivers if not required for system functionality
Ensure CONFIG_IOMMU_SVA is not enabled in kernel configuration

🔍 How to Verify

Check if Vulnerable:

Check if CONFIG_IOMMU_SVA is enabled: grep CONFIG_IOMMU_SVA /boot/config-$(uname -r) and check if idxd/uacce drivers are loaded: lsmod | grep -E 'idxd|uacce'

Check Version:

uname -r

Verify Fix Applied:

Check kernel version against patched commits from your distribution vendor and verify idxd/uacce drivers work without crashes

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages in /var/log/kern.log or dmesg
NULL pointer dereference errors in kernel logs
System crashes when using idxd or uacce drivers

Network Indicators:

None - local vulnerability only

SIEM Query:

source="kernel" AND ("NULL pointer dereference" OR "kernel panic" OR "oops") AND ("iommu" OR "sva" OR "idxd" OR "uacce")

📊 Metadata

CVE ID: CVE-2024-40945

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-476

Published: July 12, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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