SB20261022141 - Use-after-free in Linux kernel net phy driver

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-98563)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to use-after-free in the Linux kernel phylink subsystem when a failed PHY connection leaves a stale pl->phydev pointer after the PHY is detached and freed. A local user can trigger this failure condition and subsequent access to the stale pointer to potentially crash the kernel or disrupt network connectivity.

The affected failure path involves a MAC whose phylink operations implement LPI.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/4e7a4af364c2048bafb213bf0ef4a89dcbe1bfd4
• https://git.kernel.org/stable/c/671a68654a9d319d7f0d53a6321db3d9b391bdef
• https://git.kernel.org/stable/c/a940003f44e7e441c228151dd212642152700ec8