Bug 2532314 (CVE-2026-80993)

Summary:	CVE-2026-80993 kernel: net: phylink: correctly validate returned PCS in phylink_inband_caps
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's `net: phylink` component. The `phylink_inband_caps()` function does not correctly validate the return value from `mac_select_pcs`, which can return an error pointer instead of a valid Physical Coding Sublayer (PCS) object. This oversight can lead to dereferencing an invalid pointer, causing a kernel panic. A kernel panic results in a system crash, leading to a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-11 22:18:32 UTC

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.

Comment 1 Keith Grant 2026-09-14 19:56:12 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80993.mbox