PT-2025-40079 · Linux +1 · Linux Kernel +1

Published

2025-01-01

·

Updated

2025-10-03

·

CVE-2025-39905

None

No severity ratings or metrics are available. When they are, we'll update the corresponding info on the page.
Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)
Description The Linux kernel contains a flaw in the networking subsystem related to phylink. The issue involves a potential race condition when serializing concurrent writes to 
pl->phydev
with the resolver. Currently, 
phylink resolve()
relies on 
pl->state mutex
to protect against concurrent calls to 
phylink bringup phy()
or 
phylink disconnect phy()
that modify 
pl->phydev
. However, a lock inversion exists where 
pl->phydev->lock
needs to be acquired before 
pl->state mutex
, which requires dereferencing 
pl->phydev
without the protection of 
pl->state mutex
. A new lock has been added to address this, though it is currently redundant, it will become functional when 
mutex lock(&phy->lock)
is moved outside the 
mutex lock(&pl->state mutex)
section. Using the 
rtnl mutex
was considered but rejected due to potential deadlocks with 
phylink disconnect phy()
and unnecessary blocking of other kernel call paths.
Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Related Identifiers

CVE-2025-39905
ECHO-B9B2-19CF-778D

Affected Products

Debian
Linux Kernel