cbcvebase.
CVE-2025-39905
published 2025-10-01

CVE-2025-39905: In the Linux kernel, the following vulnerability has been resolved: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver Currently…

PriorityP428high7CVSS 3.1
AVLACHPRLUINSUCHIHAH
EPSS
0.10%
1.1th percentile
In the Linux kernel, the following vulnerability has been resolved: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver Currently phylink_resolve() protects itself against concurrent phylink_bringup_phy() or phylink_disconnect_phy() calls which modify pl->phydev by relying on pl->state_mutex. The problem is that in phylink_resolve(), pl->state_mutex is in a lock inversion state with pl->phydev->lock. So pl->phydev->lock needs to be acquired prior to pl->state_mutex. But that requires dereferencing pl->phydev in the first place, and without pl->state_mutex, that is racy. Hence the reason for the extra lock. Currently it is redundant, but it will serve a functional purpose once mutex_lock(&phy->lock) will be moved outside of the mutex_lock(&pl->state_mutex) section. Another alternative considered would have been to let phylink_resolve() acquire the rtnl_mutex, which is also held when phylink_bringup_phy() and phylink_disconnect_phy() are called. But since phylink_disconnect_phy() runs under rtnl_lock(), it would deadlock with phylink_resolve() when calling flush_work(&pl->resolve). Additionally, it would have been undesirable because it would have unnecessarily blocked many other call paths as well in the entire kernel, so the smaller-scoped lock was preferred.

Affected

19 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.16.8-1 (forky)linux 6.16.8-1 (forky)
linuxlinux
linuxlinux>= 5fd0f1a02e750e2db4038dee60edea669ce5aab1 < 56fe63b05ec84ae6674269d78397cec43a7a295a56fe63b05ec84ae6674269d78397cec43a7a295a
linuxlinux>= 5fd0f1a02e750e2db4038dee60edea669ce5aab1 < 0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc30ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3
linuxlinux_kernel< 6.16.86.16.8
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.16.8-16.16.8-1
msrcazl3_kernel_6.6.104.2-4_on_azure_linux_3.0
msrcazl3_kernel_6.6.112.1-2_on_azure_linux_3.0
msrcazl3_kernel_6.6.117.1-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.119.3-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.119.3-3_on_azure_linux_3.0
msrcazl3_kernel_6.6.121.1-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.126.1-1_on_azure_linux_3.0
msrcazl3_kernel_6.6.130.1-3_on_azure_linux_3.0
msrcazl3_kernel_6.6.96.2-2_on_azure_linux_3.0
msrccbl2_kernel_5.15.186.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.200.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.202.1-1_on_cbl_mariner_2.0

CVSS provenance

nvdv3.17.0HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.0HIGH
vendor_msrc7.1HIGH
vendor_debian7.0LOW
vendor_redhat7.0HIGH
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