CVE-2022-48979 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: fix array index out of bound error in DCN32 DML
[Why&How]
LinkCapacitySupport array is indexed with the number of voltage states and not the number of max DPPs. Fix the error by changing the array declaration to use the correct (larger) array size of total number of voltage states.
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Analysis
by VulDB Data Team • 01/18/2026
The vulnerability identified as CVE-2022-48979 represents a critical array index out of bounds error within the Linux kernel's display subsystem, specifically affecting the AMD display driver component. This flaw exists in the Display Core Next generation 3.2 (DCN32) Display Memory Library implementation, which is responsible for managing display-related computations and memory allocation within AMD graphics hardware. The issue stems from improper array sizing in the LinkCapacitySupport data structure, creating a potential pathway for memory corruption and system instability. The vulnerability impacts systems utilizing AMD graphics hardware with kernel versions containing the affected drm/amd/display driver code, particularly those implementing DCN32 display processing capabilities.
The technical root cause of this vulnerability lies in the incorrect sizing of the LinkCapacitySupport array within the DCN32 DML implementation. The array is being indexed using the number of voltage states rather than the total number of voltage states multiplied by the maximum number of Display Processing Units (DPPs). This fundamental miscalculation results in an array index that exceeds the allocated memory boundaries when the system attempts to access memory locations beyond the intended array limits. The flaw specifically manifests when the display driver processes configurations involving multiple DPPs, causing the indexing mechanism to reference memory locations that were not properly allocated, leading to potential memory corruption. This type of error falls under the CWE-129 weakness category, which specifically addresses issues related to improper validation of array indices, and represents a classic example of buffer overflow vulnerabilities that can be exploited to gain unauthorized access or cause system crashes.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable more severe security consequences. When the array index out of bounds error occurs, it can result in memory corruption that may be exploited by malicious actors to execute arbitrary code with kernel privileges. The vulnerability affects the display subsystem's ability to properly manage display memory allocation and bandwidth calculations for multiple display outputs, potentially leading to denial of service conditions or system crashes during normal display operations. Systems utilizing AMD graphics hardware with kernel versions containing this flaw are at risk of experiencing unexpected system behavior, including display driver failures, system hangs, or more serious security exploits that could compromise the entire system. The vulnerability's impact is particularly concerning in enterprise environments where stable display functionality and system security are paramount.
Mitigation strategies for CVE-2022-48979 should prioritize applying the official kernel patch released by the Linux kernel maintainers, which correctly adjusts the LinkCapacitySupport array size to accommodate the total number of voltage states rather than just the voltage state count. System administrators should immediately update their kernel versions to include the patched drm/amd/display driver components, particularly focusing on DCN32 implementation fixes. Additionally, organizations should implement monitoring solutions to detect potential exploitation attempts targeting this vulnerability, as the memory corruption could serve as a precursor to more sophisticated attacks. The fix aligns with ATT&CK framework technique T1068 by addressing privilege escalation pathways through kernel-level vulnerabilities, and follows security best practices outlined in the NIST Cybersecurity Framework for vulnerability remediation. Regular kernel updates and security assessments should be implemented to prevent similar issues from arising in future versions, ensuring that display driver components maintain proper memory management practices and array boundary validations.