CVE-2025-21954
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk37th percentile - higher than 37% of all known CVEs
Summary
In the Linux kernel's netmem subsystem, there is no protection against transmitting (xmit) packets that are unreadable by the CPU. Forwarding such a packet to a network driver can cause DMA operations on invalid addresses.
Risk Assessment
An attacker could remotely cause memory corruption or system crash by redirecting network traffic containing netmem packets that should not enter the TX path.
Recommendation
Apply the Linux kernel patch for CVE-2025-21954 that prevents transmission of unreadable netmem packets by checking before xmit.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: netmem: prevent TX of unreadable skbs Currently on stable trees we have support for netmem/devmem RX but not TX. It is not safe to forward/redirect an RX unreadable netmem packet into the device's TX path, as the device may call dma-mapping APIs on dma addrs that should not be passed to it. Fix this by preventing the xmit of unreadable skbs. Tested by configuring tc redirect: sudo tc qdisc add dev eth1 ingress sudo tc filter add dev eth1 ingress protocol ip prio 1 flower ip_proto \ tcp src_ip 192.168.1.12 action mirred egress redirect dev eth1 Before, I see unreadable skbs in the driver's TX path passed to dma mapping APIs. After, I don't see unreadable skbs in the driver's TX path passed to dma mapping APIs.