CVE-2025-39687
📋 TL;DR
This CVE addresses an information disclosure vulnerability in the Linux kernel's AS73211 light sensor driver. The driver fails to properly zero out unused portions of a buffer before copying it to user-accessible memory, potentially leaking kernel memory contents to unprivileged users. Systems using the affected driver are vulnerable.
💻 Affected Systems
- Linux kernel with AS73211 light sensor driver
📦 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 →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 memory contents including sensitive data, cryptographic keys, or process information could be leaked to unprivileged users, potentially enabling further privilege escalation attacks.
Likely Case
Limited information disclosure of kernel memory contents to users with access to the sensor device, potentially revealing system state or other non-critical data.
If Mitigated
No information disclosure occurs; users can only access legitimate sensor data as intended.
🎯 Exploit Status
Exploitation requires local access and ability to interact with the sensor device. No public exploits are known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing the fix commits: 433b99e92294, 83f14c4ca1ad, 8acd9a0eaa8c, 99b508340d0d, cce55ca4e7a2
Vendor Advisory: https://git.kernel.org/stable/c/433b99e922943efdfd62b9a8e3ad1604838181f2
Restart Required: Yes
Instructions:
1. Update to a kernel version containing the fix commits. 2. Reboot the system. 3. Verify the driver is properly loaded and functioning.
🔧 Temporary Workarounds
Disable AS73211 driver
linuxPrevent loading of the vulnerable driver module
echo 'blacklist as73211' >> /etc/modprobe.d/blacklist.conf
rmmod as73211
Restrict device access
linuxLimit access to the sensor device to trusted users only
chmod 600 /dev/iio:device*
chown root:root /dev/iio:device*
🧯 If You Can't Patch
- Restrict access to the sensor device to only necessary users/groups
- Monitor for unusual access patterns to the IIO device interface
🔍 How to Verify
Check if Vulnerable:
Check if AS73211 driver is loaded: lsmod | grep as73211. If loaded, check kernel version against patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and driver functions normally with sensor hardware.📡 Detection & Monitoring
Log Indicators:
- Unusual access patterns to /dev/iio:device* files
- Kernel oops or warnings related to as73211 driver
Network Indicators:
- Not applicable - local vulnerability only
SIEM Query:
process.name='cat' AND file.path='/dev/iio:device*' AND NOT user.name IN ('root', 'authorized_user')🔗 References
- https://git.kernel.org/stable/c/433b99e922943efdfd62b9a8e3ad1604838181f2
- https://git.kernel.org/stable/c/83f14c4ca1ad78fcfb3e0de07d6d8a0c59550fc2
- https://git.kernel.org/stable/c/8acd9a0eaa8c9a28e385c0a6a56bb821cb549771
- https://git.kernel.org/stable/c/99b508340d0d1b9de0856c48c77898b14c0df7cf
- https://git.kernel.org/stable/c/cce55ca4e7a221d5eb2c0b757a868eacd6344e4a
- https://git.kernel.org/stable/c/d8c5d87a431596e0e02bd7fe3bff952b002a03bb
- https://git.kernel.org/stable/c/fd441fd972067f80861a0b66605c0febb0d038dd
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
