CVE-2025-21743
📋 TL;DR
A buffer overflow vulnerability in the Linux kernel's USB network driver for iPhone tethering (ipheth) could allow out-of-bounds memory reads. This affects Linux systems with the ipheth driver loaded, typically when iPhone tethering is used. The vulnerability stems from improper bounds checking in DPE length validation.
💻 Affected Systems
- Linux kernel
📦 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
Kernel memory disclosure leading to information leakage, potential privilege escalation, or system crash.
Likely Case
System instability, kernel panic, or denial of service when processing malformed USB packets during iPhone tethering.
If Mitigated
No impact if ipheth driver is not loaded or iPhone tethering is not used.
🎯 Exploit Status
Requires USB device access or network access to send malformed packets to the ipheth interface. No public exploits known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 18bf6f5cce3172cb303c3f0551aa9443d5ed74f8, c219427ed296f94bb4b91d08626776dc7719ee27, d677e7dd59ad6837496f5a02d8e5d39824278dfd, d824a964185910e317287f034c0a439c08b4fe49
Vendor Advisory: https://git.kernel.org/stable/c/18bf6f5cce3172cb303c3f0551aa9443d5ed74f8
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify ipheth module is not loaded if not needed.
🔧 Temporary Workarounds
Disable ipheth module
LinuxPrevent loading of vulnerable ipheth driver if iPhone tethering is not required
echo 'blacklist ipheth' >> /etc/modprobe.d/blacklist-ipheth.conf
rmmod ipheth
🧯 If You Can't Patch
- Disable iPhone tethering functionality completely
- Restrict USB device access to trusted devices only
🔍 How to Verify
Check if Vulnerable:
Check if ipheth module is loaded: lsmod | grep iphethCheck Version:
uname -rVerify Fix Applied:
Check kernel version contains fix commits or is newer than vulnerable versions📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System crashes during USB tethering
Network Indicators:
- Unusual USB device enumeration patterns
- Malformed packet traffic to ipheth interfaces
SIEM Query:
source="kernel" AND ("ipheth" OR "USB tethering" OR "kernel panic")