CVE-2025-39680
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in the Linux kernel's RTL9300 I2C driver. An attacker with local access can trigger memory corruption by providing specially crafted data to the i2c-dev interface. This affects systems using the RTL9300 I2C controller driver.
💻 Affected Systems
- Linux kernel with RTL9300 I2C 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 →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to kernel-level code execution, potentially leading to full system compromise.
Likely Case
Kernel panic causing system crash/denial of service, or limited memory corruption.
If Mitigated
No impact if proper kernel hardening (like SMEP/SMAP) prevents escalation, or if driver not loaded.
🎯 Exploit Status
Requires local access and knowledge of i2c-dev interface. Similar to referenced CVEs.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 071e43fcba5ddd9a7813e6cc0aa10299eae41b21 or 57f312b955938fc4663f430cb57a71f2414f601b
Vendor Advisory: https://git.kernel.org/stable/c/071e43fcba5ddd9a7813e6cc0aa10299eae41b21
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable RTL9300 I2C driver
linuxPrevent loading of vulnerable driver module
echo 'blacklist rtl9300_i2c' >> /etc/modprobe.d/blacklist-rtl9300.conf
rmmod rtl9300_i2c
Restrict i2c-dev access
linuxLimit access to i2c-dev interface to trusted users only
chmod 600 /dev/i2c-*
chown root:root /dev/i2c-*
🧯 If You Can't Patch
- Implement strict access controls on /dev/i2c-* devices
- Enable kernel hardening features like SMEP/SMAP/KASLR
🔍 How to Verify
Check if Vulnerable:
Check if rtl9300_i2c module is loaded: lsmod | grep rtl9300_i2cCheck Version:
uname -rVerify Fix Applied:
Check kernel version includes fix commits or is newer than vulnerable versions📡 Detection & Monitoring
Log Indicators:
- Kernel oops/panic messages
- Unexpected i2c-dev access in audit logs
Network Indicators:
- None - local vulnerability
SIEM Query:
Process accessing /dev/i2c-* from untrusted users