CVE-2025-21954: netmem: prevent TX of unreadable skbs
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 ipproto \ tcp srcip 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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21954?
CVE-2025-21954 is considered a security vulnerability in the Linux kernel that affects the forwarding of unreadable packets.
How do I fix CVE-2025-21954?
To fix CVE-2025-21954, ensure you update your Linux kernel to the latest stable version where the vulnerability has been resolved.
Which software is affected by CVE-2025-21954?
CVE-2025-21954 affects the Linux Kernel, particularly in its handling of netmem and devmem.
What does CVE-2025-21954 impact?
CVE-2025-21954 impacts the TX path of unreadable netmem packets, potentially leading to security risks.
Is CVE-2025-21954 patched in stable releases?
Yes, CVE-2025-21954 has been resolved in stable tree releases of the Linux kernel.