CVE-2025-21954
📋 TL;DR
This Linux kernel vulnerability allows unreadable network memory packets to be incorrectly transmitted through the TX path, potentially causing DMA mapping API errors. It affects systems using netmem/devmem RX functionality with specific traffic control configurations. Attackers could potentially cause system instability or crashes by exploiting this condition.
💻 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 →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
System crash or kernel panic due to invalid DMA operations, potentially leading to denial of service.
Likely Case
System instability, packet loss, or performance degradation when specific traffic control rules are applied.
If Mitigated
Minor performance impact or no effect if proper kernel patches are applied.
🎯 Exploit Status
Exploitation requires local network configuration privileges and specific traffic control rules.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 1c17c8ced25c5fbe424c7ad7ea11d33014a986b1, 454825019d2f0c59e5174ece9e713f45ad80beff, f3600c867c99a2cc8038680ecf211089c50e7971
Vendor Advisory: https://git.kernel.org/stable/c/1c17c8ced25c5fbe424c7ad7ea11d33014a986b1
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Remove vulnerable tc configurations
linuxRemove traffic control rules that use redirect actions on affected interfaces
sudo tc qdisc del dev eth1 ingress
sudo tc filter del dev eth1 ingress
🧯 If You Can't Patch
- Avoid using tc redirect actions on network interfaces
- Monitor system logs for DMA mapping errors and network instability
🔍 How to Verify
Check if Vulnerable:
Check if tc redirect rules are configured and kernel version is affectedCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits and test tc redirect functionality📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing DMA mapping errors
- Network driver errors in dmesg
Network Indicators:
- Unusual packet loss on interfaces with tc redirect rules
SIEM Query:
source="kernel" AND ("dma" OR "netmem" OR "skb") AND ("error" OR "warning")