Bug 2562666 (CVE-2026-99118)

Summary:	CVE-2026-99118 kernel: drm/i915/dmc: Harden DMC firmware payload parsing
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 Linux kernel's i915 graphics driver. When parsing Display Microcontroller (DMC) firmware images, the driver does not properly validate payload sizes or check for integer multiplication overflow during size calculations. A local user with the ability to supply a malformed firmware file could exploit this flaw, potentially leading to memory corruption or a Denial of Service (DoS) via a system crash.	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 2026-10-28 10:46:08 UTC

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

drm/i915/dmc: Harden DMC firmware payload parsing

Validate the conversion of the DMC firmware size from dwords to bytes
using check_mul_overflow() before calculating the firmware payload size.

Reject zero-length payloads and zero MMIO counts in the DMC firmware
header so malformed firmware is caught early. Also set dmc_fw_size only
after the payload allocation succeeds.

(cherry picked from commit efde6601a1f1daedfe3dcc2816c934ddb44e3eef)