Vulnerability Monitor

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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() 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.

Published

2025-04-01T16:15:22.790

Last Modified

2025-10-31T18:08:21.410

Status

Analyzed

Source

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Severity

CVSSv3.1: 5.5 (MEDIUM)

Weaknesses
  • Type: Primary
    CWE-476
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System linux linux_kernel < 6.12.19 Yes
Operating System linux linux_kernel < 6.13.7 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
Operating System linux linux_kernel 6.14 Yes
References