cbcvebase.
CVE-2025-21921
published 2025-04-01

CVE-2025-21921: In the Linux kernel, the following vulnerability has been resolved: net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device ethnl_req_get_phydev()…

PriorityP422medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.19%
8.9th percentile
In the Linux kernel, the following vulnerability has been resolved: net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device ethnl_req_get_phydev() is used to lookup a phy_device, in the case an ethtool netlink command targets a specific phydev within a netdev's topology. It takes as a parameter a const struct nlattr *header that's used for error handling : if (!phydev) { NL_SET_ERR_MSG_ATTR(extack, header, "no phy matching phyindex"); return ERR_PTR(-ENODEV); } In the notify path after a ->set operation however, there's no request attributes available. The typical callsite for the above function looks like: phydev = ethnl_req_get_phydev(req_base, tb[ETHTOOL_A_XXX_HEADER], info->extack); So, when tb is NULL (such as in the ethnl notify path), we have a nice crash. It turns out that there's only the PLCA command that is in that case, as the other phydev-specific commands don't have a notification. This commit fixes the crash by passing the cmd index and the nlattr array separately, allowing NULL-checking it directly inside the helper.

Affected

10 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.19-1 (forky)linux 6.12.19-1 (forky)
linuxlinux
linuxlinux>= c15e065b46dc4e19837275b826c1960d55564abd < 639c70352958735addbba5ae7dd65985da96e061639c70352958735addbba5ae7dd65985da96e061
linuxlinux>= c15e065b46dc4e19837275b826c1960d55564abd < 1f458fa42c29144cef280e05bc49fc21b873d8971f458fa42c29144cef280e05bc49fc21b873d897
linuxlinux>= c15e065b46dc4e19837275b826c1960d55564abd < 637399bf7e77797811adf340090b561a8f9d1213637399bf7e77797811adf340090b561a8f9d1213
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 6.12 < 6.12.196.12.19
linuxlinux_kernel>= 6.13 < 6.13.76.13.7

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5LOW
vendor_redhat5.5MEDIUM
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