Bug 2536522 (CVE-2026-90289)

Summary:	CVE-2026-90289 kernel: drm/amd/display: Resize MST HDCP per-connector arrays to 32
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
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 `drm/amd/display` component of the Linux kernel. An off-by-one error in the sizing of Multi-Stream Transport (MST) High-bandwidth Digital Content Protection (HDCP) per-connector arrays could lead to incorrect array handling. This issue stems from a discrepancy between the intended maximum display count and the actual array size, causing a mismatch with the Digital Rights Management (DRM) core's connector support.	Story Points:	---
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Last Closed:		Type:	---
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-17 18:16:59 UTC

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

drm/amd/display: Resize MST HDCP per-connector arrays to 32

AMDGPU_DM_MAX_DISPLAY_INDEX is 31. It suggest a maximum number of
32 connectors. But the way it's used is like MAX_DISPLAY_COUNT.
Hence we're off by one with DRM core, which supports a max of 32
connectors.

Rename AMDGPU_DM_MAX_DISPLAY_INDEX to AMDGPU_DM_MAX_DISPLAY_COUNT
to match its actual use, and increase the size to 32 to match the
originally intended size.

Comment 1 gkamathe 2026-09-22 18:32:17 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90289.mbox