CVE-2022-49757 in Linux
Summary
by MITRE • 03/27/2025
In the Linux kernel, the following vulnerability has been resolved:
EDAC/highbank: Fix memory leak in highbank_mc_probe()
When devres_open_group() fails, it returns -ENOMEM without freeing memory allocated by edac_mc_alloc().
Call edac_mc_free() on the error handling path to avoid a memory leak.
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Analysis
by VulDB Data Team • 12/06/2025
The vulnerability identified as CVE-2022-49757 resides within the Linux kernel's Error Detection and Correction subsystem, specifically affecting the highbank memory controller driver. This issue demonstrates a classic memory management flaw that can lead to resource exhaustion and system instability. The problem manifests in the EDAC/highbank driver where the memory allocation and error handling paths do not properly coordinate, creating a scenario where allocated memory remains unreleased when allocation failures occur.
The technical flaw occurs in the highbank_mc_probe() function where devres_open_group() is called to establish a device resource group for memory management. When this function encounters an allocation failure and returns -ENOMEM, the subsequent error handling code fails to invoke edac_mc_free() to release memory previously allocated by edac_mc_alloc(). This creates a memory leak where the kernel's memory management system retains references to allocated memory blocks that should be freed, leading to gradual memory consumption and potential system resource depletion.
This vulnerability operates at the kernel level and affects systems utilizing the highbank memory controller architecture, particularly those implementing error detection and correction mechanisms for memory subsystems. The operational impact extends beyond simple memory waste, as sustained memory leaks can degrade system performance, potentially leading to memory exhaustion conditions that might cause system crashes or forced reboots. The issue is particularly concerning in server environments or embedded systems where memory resources are constrained and system reliability is paramount.
The fix implemented addresses the root cause by ensuring proper error handling flow in the memory allocation path. When devres_open_group() fails, the code now properly calls edac_mc_free() to release previously allocated memory resources before propagating the error condition. This remediation follows established kernel development practices for resource management and error handling, ensuring that all allocated resources are properly cleaned up regardless of the execution path taken. The solution aligns with common security principles and kernel coding standards that require defensive programming practices to prevent resource leaks.
From a cybersecurity perspective, this vulnerability represents a potential denial of service vector that could be exploited by malicious actors to gradually consume system resources. While the immediate impact may appear limited to memory consumption, the cumulative effect of such leaks can compromise system availability and stability. The vulnerability falls under CWE-401, which specifically addresses improper deallocation of memory, and aligns with ATT&CK technique T1499.001 for resource exhaustion attacks. The fix demonstrates proper kernel memory management practices that prevent resource exhaustion conditions and maintain system integrity.
The resolution of CVE-2022-49757 through the addition of proper error handling and resource cleanup represents a fundamental improvement in kernel stability and security posture. By ensuring that all allocated resources are properly released during error conditions, the fix prevents potential exploitation scenarios while maintaining the driver's functionality. This type of vulnerability highlights the critical importance of comprehensive error handling in kernel space code where resource management failures can have cascading effects on system stability and security. The fix serves as a model for other kernel subsystems to implement similar defensive programming practices to prevent similar memory leak scenarios.