CVE-2025-21954

netmem: prevent TX of unreadable skbs

Description

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.

N/A

CVSS

Severity:

EPSS 0.02%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/454825019d2f0c59e5174ece9e713f45ad80beff
https://git.kernel.org/stable/c/1c17c8ced25c5fbe424c7ad7ea11d33014a986b1
https://git.kernel.org/stable/c/f3600c867c99a2cc8038680ecf211089c50e7971

Frequently Asked Questions

What is the severity of CVE-2025-21954?: CVE-2025-21954 has not yet been assigned a CVSS score.
How to fix CVE-2025-21954?: To fix CVE-2025-21954, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-21954 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2025-21954 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-21954?: CVE-2025-21954 affects Linux Linux, Linux Linux.

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