Medium [CVE-2026-72391] free mii_bus in sfp_i2c_mdiobus_destroy
This medium-severity Red Hat Linux advisory covers CVE-2026-72391.
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Summary
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.
A memory leak vulnerability exists in the SFP (Small Form-Factor Pluggable) module handling within the networking subsystem. When a copper/RollBall SFP module is hot-removed, the associated MII (Media Independent Interface) bus structure is not properly deallocated.
This oversight leads to a memory leak, which could potentially result in a Denial of Service (DoS) over an extended period due to resource exhaustion. Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-772.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
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