CVE-2022-49828 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
hugetlbfs: don't delete error page from pagecache
This change is very similar to the change that was made for shmem [1], and
it solves the same problem but for HugeTLBFS instead.
Currently, when poison is found in a HugeTLB page, the page is removed from the page cache. That means that attempting to map or read that hugepage in the future will result in a new hugepage being allocated instead of notifying the user that the page was poisoned. As [1] states,
this is effectively memory corruption.
The fix is to leave the page in the page cache. If the user attempts to use a poisoned HugeTLB page with a syscall, the syscall will fail with EIO, the same error code that shmem uses. For attempts to map the page, the thread will get a BUS_MCEERR_AR SIGBUS.
[1]: commit a76054266661 ("mm: shmem: don't truncate page if memory failure happens")
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Analysis
by VulDB Data Team • 03/20/2026
The vulnerability described in CVE-2022-49828 affects the Linux kernel's HugeTLBFS implementation, representing a critical memory corruption issue that stems from improper handling of poisoned huge pages within the page cache mechanism. This flaw exists in the kernel's memory management subsystem where the hugetlbfs filesystem fails to properly maintain poisoned pages in the page cache, leading to potentially catastrophic consequences for system stability and data integrity. The vulnerability directly impacts the kernel's ability to correctly report memory errors and maintain consistent memory state across system operations.
The technical implementation flaw occurs when memory errors or poison conditions are detected within HugeTLB pages, causing the kernel to remove these pages from the page cache entirely rather than preserving them in a failed state. This behavior creates a fundamental inconsistency where subsequent access attempts to the same memory region result in allocation of new pages instead of proper error reporting. The mechanism differs significantly from the established shmem implementation, which correctly handles memory failures by retaining pages in the cache with appropriate error signaling. This inconsistency represents a design flaw that violates the expected behavior patterns within the Linux kernel's memory management architecture.
The operational impact of this vulnerability extends beyond simple memory corruption to encompass potential system crashes, data loss, and unauthorized access to memory regions. When a poisoned HugeTLB page is encountered, the system's failure to maintain proper error states means that applications may continue to operate with corrupted memory, leading to unpredictable behavior and potential security exploits. The fix implemented addresses this by maintaining poisoned pages in the page cache while ensuring appropriate error codes are returned to user-space applications, specifically using EIO for system calls and SIGBUS for mapping attempts. This approach aligns with established kernel memory management practices and maintains consistency with the shmem implementation referenced in the commit.
The vulnerability demonstrates a clear violation of the principle of least privilege and proper error handling within kernel space, where memory management operations should maintain system integrity even in failure conditions. The fix directly addresses this issue by ensuring that when memory errors occur in HugeTLB pages, the system preserves the error state rather than removing the page entirely, thereby preventing the propagation of corrupted memory references. This behavior conforms to industry standards and best practices for kernel memory management, where error conditions should be properly reported and handled rather than silently masked or removed from the system state. The solution implements a robust error handling mechanism that maintains system stability while providing clear feedback to applications about memory corruption events.
From a cybersecurity perspective, this vulnerability represents a potential attack vector for privilege escalation or denial of service attacks, as malicious actors could exploit the improper memory handling to cause system instability or gain unauthorized access to protected memory regions. The fix addresses these concerns by ensuring that memory failures are properly reported and handled, preventing attackers from exploiting the inconsistent behavior to manipulate system memory state. The implementation follows established security principles and aligns with the ATT&CK framework's concepts of privilege escalation and resource exhaustion, where proper memory management prevents exploitation of memory corruption vulnerabilities. This vulnerability highlights the critical importance of consistent error handling across kernel subsystems and demonstrates how seemingly small implementation differences can lead to significant security and stability implications in complex operating system environments.