CVE-2025-39934 – A race condition in the Linux kernel's ANX7625 ... (How to Fix)

Q: What is the severity of CVE-2025-39934?

CVE-2025-39934 has a CVSS score of 5.5 (MEDIUM). A race condition in the Linux kernel's ANX7625 DisplayPort bridge driver allows an interrupt to occur before device initialization completes, potentially causing a NULL pointer dereference. This affects systems using the ANX7625 bridge chip with vulnerable kernel versions. The vulnerability could lead to kernel crashes or system instability.

📋 TL;DR

A race condition in the Linux kernel's ANX7625 DisplayPort bridge driver allows an interrupt to occur before device initialization completes, potentially causing a NULL pointer dereference. This affects systems using the ANX7625 bridge chip with vulnerable kernel versions. The vulnerability could lead to kernel crashes or system instability.

💻 Affected Systems

Products:

Linux kernel with ANX7625 bridge driver

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: Only affects systems with ANX7625 DisplayPort bridge hardware. Most systems without this specific hardware are not vulnerable.

📦 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 →

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 requiring physical reboot.

🟠

Likely Case

System instability or crash when using ANX7625 bridge hardware, requiring reboot to recover.

🟢

If Mitigated

Minor system instability that self-recovers or requires driver reload.

🌐 Internet-Facing: LOW - Requires local access or specific hardware interaction.

🏢 Internal Only: MEDIUM - Could affect workstations/servers with vulnerable hardware and kernel versions.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires triggering an interrupt during driver initialization, which is timing-dependent and hardware-specific.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits: 0da73f7827691a5e2265b110d5fe12f29535ec92, 15a77e1ab0a994d69b471c76b8d01117128dda26, 1a7ea294d57fb61485d11b3f2241d631d73025cb, 51a501e990a353a4f15da6bab295b28e5d118f64, a10f910c77f280327b481e77eab909934ec508f0

Vendor Advisory: https://git.kernel.org/stable/c/0da73f7827691a5e2265b110d5fe12f29535ec92

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Reboot system. 3. Verify kernel version and that ANX7625 driver loads without errors.

🔧 Temporary Workarounds

Disable ANX7625 driver

linux

Prevent loading of the vulnerable driver if hardware is not needed

echo 'blacklist anx7625' >> /etc/modprobe.d/blacklist-anx7625.conf
update-initramfs -u
reboot

🧯 If You Can't Patch

Ensure systems without ANX7625 hardware are not affected
Monitor system logs for kernel panic or oops messages related to anx7625

🔍 How to Verify

Check if Vulnerable:

Check if ANX7625 hardware is present and kernel version is vulnerable: lspci | grep -i anx7625 && uname -r

Check Version:

uname -r

Verify Fix Applied:

Check kernel version includes fix commits and driver loads without errors: dmesg | grep anx7625

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages mentioning anx7625
NULL pointer dereference in kernel logs
System crash/panic logs

Network Indicators:

None - local vulnerability only

SIEM Query:

source="kernel" AND ("anx7625" OR "NULL pointer dereference")

📊 Metadata

CVE ID: CVE-2025-39934

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

EPSS Score: 0.03% exploit probability (9.1th percentile)

Published: October 4, 2025

Last Updated: January 23, 2026

🔗 References

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