CVE-2026-80993

Received Received - Intake

Kernel panic due to improper PCS validation in Linux kernel

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net: phylink: correctly validate returned PCS in phylink_inband_caps In phylink_inband_caps(), the PCS returned by mac_select_pcs is only checked if NULL but mac_select_pcs can also return an error pointer. This can cause a kernel panic as phylink_pcs_inband_caps() only checks if passed PCS is not NULL and directly dereference ops from the phylink_pcs struct. Use the IS_ERR_OR_NULL macro to address both case where the returned PCS can be NULL or an error pointer and prevent a kernel panic.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-11

Last Modified

2026-09-11

Generated

2026-09-12

AI Q&A

2026-09-12

EPSS Evaluated

N/A

NVD

CVE-2026-80993

EUVD

EUVD-2026-76316

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability is in the Linux kernel's phylink subsystem. It occurs in the phylink_inband_caps() function where the PCS (Physical Coding Sublayer) returned by mac_select_pcs is not properly validated. The function only checks if the PCS is NULL but does not handle error pointers, which can lead to a kernel panic when the PCS is dereferenced.

Detection Guidance

This vulnerability is specific to the Linux kernel's phylink subsystem and may not have direct detection commands. Monitor kernel logs for crashes or panics related to phylink or network interfaces. Check for kernel oops messages or unexpected network interface failures.

Impact Analysis

This vulnerability can cause a kernel panic, leading to system crashes and potential denial of service. If exploited, it could disrupt network operations and require a system reboot to recover.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for CVE-2026-80993. The fix involves using IS_ERR_OR_NULL to validate the PCS pointer in phylink_inband_caps. If immediate patching is not possible, consider disabling affected network interfaces or restricting network operations until the update is applied.

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