Bug 2535194 (CVE-2026-89806)

Summary: CVE-2026-89806 kernel: drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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   
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Doc Text:
A flaw was found in the Linux kernel's `drm/sysfb: ofdrm` component. This vulnerability occurs due to an integer overflow during the framebuffer size calculation when both `linebytes` and `height` values are excessively large. This can lead to undefined behavior within the kernel, potentially impacting system stability or allowing for further exploitation.
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Description OSIDB Bzimport 2026-09-16 11:22:11 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation

The framebuffer size calculation `fb_size = linebytes * height` can
overflow when both values are large (e.g., 46341 * 46341 > INT_MAX).
Since linebytes and height are both int types, the multiplication is
performed as int * int, which results in undefined behavior on overflow.

Use check_mul_overflow() to detect and prevent this overflow, consistent
with the approach used in simpledrm.c and corebootdrm.c.
Comment 1 Mauro Matteo Cascella 2026-09-21 15:25:03 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89806.mbox