CVE-2025-38473

Q: What is the severity of CVE-2025-38473?

CVE-2025-38473 has a CVSS score of 5.5 (MEDIUM). This CVE describes a null pointer dereference vulnerability in the Linux kernel's Bluetooth L2CAP socket implementation. When exploited, it can cause a kernel panic leading to denial of service. Systems running vulnerable Linux kernel versions with Bluetooth enabled are affected.

5.5 MEDIUM

Denial of Service

📋 TL;DR

This CVE describes a null pointer dereference vulnerability in the Linux kernel's Bluetooth L2CAP socket implementation. When exploited, it can cause a kernel panic leading to denial of service. Systems running vulnerable Linux kernel versions with Bluetooth enabled are affected.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific vulnerable kernel versions are not explicitly listed in the CVE description, but references point to multiple stable kernel commits suggesting various affected versions.

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with Bluetooth functionality enabled and in use. The vulnerability is triggered during Bluetooth connection resumption.

📦 What is this software?

Debian Linux by Debian

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Linux Kernel by Linux

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⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash and denial of service, potentially requiring physical access to restart the system.

🟠

Likely Case

System crash or instability when Bluetooth connections are established or resumed, requiring reboot to restore functionality.

🟢

If Mitigated

No impact if Bluetooth is disabled or the system is patched; otherwise, potential service disruption.

🌐 Internet-Facing: LOW - This vulnerability requires local Bluetooth access and cannot be exploited remotely over the internet.

🏢 Internal Only: MEDIUM - Attackers with local network access could potentially trigger the vulnerability via Bluetooth, but requires proximity and Bluetooth connectivity.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires Bluetooth access and specific timing conditions during connection resumption. The vulnerability was discovered by syzbot fuzzing.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple kernel versions with fixes referenced in the CVE (commits: 262cd18f5f7e, 2b27b3890066, 3a4eca2a1859, 6d63901dcd59, a0075accbf0d)

Vendor Advisory: https://git.kernel.org/stable/c/262cd18f5f7ede6a586580cadc5d0799e52e2e7c

Restart Required: Yes

Instructions:

1. Update Linux kernel to a version containing the fix. 2. Check your distribution's security advisories for specific patched kernel versions. 3. Reboot the system after kernel update.

🔧 Temporary Workarounds

Disable Bluetooth

linux

Completely disable Bluetooth functionality to prevent exploitation

systemctl stop bluetooth
systemctl disable bluetooth
rfkill block bluetooth

Blacklist Bluetooth kernel module

linux

Prevent Bluetooth kernel module from loading

echo 'blacklist btusb' >> /etc/modprobe.d/blacklist-bluetooth.conf
echo 'blacklist bluetooth' >> /etc/modprobe.d/blacklist-bluetooth.conf
update-initramfs -u

🧯 If You Can't Patch

Disable Bluetooth functionality completely on affected systems
Implement network segmentation to isolate Bluetooth-enabled devices from critical systems

🔍 How to Verify

Check if Vulnerable:

Check kernel version and compare with distribution security advisories. Vulnerable if running an affected kernel version with Bluetooth enabled.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated to a patched version and test Bluetooth functionality for stability.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
KASAN null-ptr-deref reports in kernel logs
Bluetooth subsystem crashes

Network Indicators:

Unexpected Bluetooth disconnections
Bluetooth service failures

SIEM Query:

source="kernel" AND ("KASAN: null-ptr-deref" OR "l2cap_sock_resume_cb" OR "Bluetooth crash")

📊 Metadata

CVE ID: CVE-2025-38473

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: 0.02% exploit probability (4th percentile)

Published: July 28, 2025

Last Updated: December 22, 2025

🔗 References

https://git.kernel.org/stable/c/262cd18f5f7ede6a586580cadc5d0799e52e2e7c Patch
https://git.kernel.org/stable/c/2b27b389006623673e8cfff4ce1e119cce640b05 Patch
https://git.kernel.org/stable/c/3a4eca2a1859955c65f07a570156bd2d9048ce33 Patch
https://git.kernel.org/stable/c/6d63901dcd592a1e3f71d7c6d78f9be5e8d7eef0 Patch
https://git.kernel.org/stable/c/a0075accbf0d76c2dad1ad3993d2e944505d99a0 Patch
https://git.kernel.org/stable/c/ac3a8147bb24314fb3e84986590148e79f9872ec Patch
https://git.kernel.org/stable/c/b97be7ee8a1cd96b89817cbd64a9f5cc16c17d08 Patch
https://git.kernel.org/stable/c/c4f16f6b071a74ac7eefe5c28985285cbbe2cd96 Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Third Party Advisory,Mailing List
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory,Mailing List

📋 TL;DR

💻 Affected Systems

📦 What is this software?

Debian Linux by Debian

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

Linux Kernel by Linux

⚠️ Risk & Real-World Impact

Worst Case

Likely Case

If Mitigated

🎯 Exploit Status

🛠️ Fix & Mitigation

✅ Official Fix

Instructions:

🔧 Temporary Workarounds

Disable Bluetooth

Blacklist Bluetooth kernel module

🧯 If You Can't Patch

🔍 How to Verify

Check if Vulnerable:

Check Version:

Verify Fix Applied:

📡 Detection & Monitoring

Log Indicators:

Network Indicators:

SIEM Query:

📊 Metadata

🔗 References

📤 Share & Export

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