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CVE-2026-98563

In the Linux kernel, the following vulnerability has been resolved: net: phylink: record the PHY only once bringup cannot fail phylink_bringup_phy() stores the PHY in pl->phydev before its last f…

Published Oct 18, 2026EPSS 0.20%

Overview

CVE-2026-98563 is a known-severity vulnerability. It was published on October 18, 2026.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: phylink: record the PHY only once bringup cannot fail

phylink_bringup_phy() stores the PHY in pl->phydev before its last

fallible step: on a MAC whose phylink ops implement LPI,

phy_eee_rx_clock_stop() can fail with a real MDIO error. The callers

unwind with phy_detach(), which knows nothing about pl->phydev, so a

pointer to a PHY that is no longer attached outlives the failed

connect.

What that costs depends on how the caller got here.

phylink_connect_phy() goes through phylink_attach_phy(), which refuses

to attach while pl->phydev is set, turning a transient MDIO error into

a permanent -EBUSY. The SFP path is worse than that: sfp_sm_probe_phy()

answers the failure with phy_device_remove() and phy_device_free(), and

it assigns sfp->mod_phy only past that error return, so nothing clears

pl->phydev and it is left pointing at a freed phy_device that

phylink_resolve() and the ethtool helpers go on reading.

phylink

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently asked questions

What is CVE-2026-98563?

CVE-2026-98563 is a known-severity vulnerability. It was published on October 18, 2026.

How severe is CVE-2026-98563?

CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.

How do I fix or remediate CVE-2026-98563?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-98563?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-98563 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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