Bug 2535327 (CVE-2026-89821)

Summary: CVE-2026-89821 kernel: drm/amd/display: avoid divide-by-zero in __is_lut_linear()
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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A flaw was found in the Linux kernel's drm/amd/display component. This vulnerability occurs when the __is_lut_linear() function processes a Look-Up Table (LUT) with a single entry, triggering a division-by-zero error. This error causes the kernel to crash, leading to a Denial of Service (DoS) for the system. A local attacker could potentially exploit this vulnerability.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-16 12:04:17 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amd/display: avoid divide-by-zero in __is_lut_linear()

__is_lut_linear() computes the expected value of each entry with

	expected = i * MAX_DRM_LUT_VALUE / (size - 1);

If it is ever called with a single-entry LUT, size - 1 is zero and the
kernel takes a divide error (#DE). A LUT with fewer than two entries
cannot describe a linear mapping anyway, so return false early instead
of dividing by zero.
Comment 1 gkamathe 2026-09-17 09:25:13 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89821.mbox