CVE-2026-72391net: phy: sfp: free mii_bus in sfp_i2c_mdiobus_destroy

Official 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().

Affected packages & fixed versions

Affected products (as reported)

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