CVE-20XX-?
agent?

CVE-2025-21921

5.5 MEDIUM 0.2% exploit odds Fix listed Memory safety OS & kernel

What it is

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.

At a glance

Exploitability
Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
Exploit odds
0.2% chance of exploitation in the next 30 days (EPSS).
Fix
A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

  1. PublishedDisclosed publicly on CVE.org and NVD
  2. Last updatedMost recent change to the record

Why it ranks here

Details

Published
Last modified
Exploit probability
0.2% · EPSS, next 30 days
Weakness
CWE-476 · NULL pointer dereference
Record status
Analyzed

Affected

Attack profile CVSS 3.1 · 5.5

Attack vector
Local
Complexity
Low
Privileges needed
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Raw vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-21921.md and follow it. Check whether this project is affected by CVE-2025-21921. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

· More options · Status badge

Meme: I wake up, CVE-2025-21921
Download Square Reddit

Fix and advisories

References

NVD record · CVE.org record