CVE-2024-50272 in Linux
Summary
by MITRE • 11/19/2024
In the Linux kernel, the following vulnerability has been resolved:
filemap: Fix bounds checking in filemap_read()
If the caller supplies an iocb->ki_pos value that is close to the filesystem upper limit, and an iterator with a count that causes us to overflow that limit, then filemap_read() enters an infinite loop.
This behaviour was discovered when testing xfstests generic/525 with the "localio" optimisation for loopback NFS mounts.
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Analysis
by VulDB Data Team • 10/22/2025
The vulnerability identified as CVE-2024-50272 represents a critical bounds checking flaw within the Linux kernel's filemap subsystem, specifically affecting the filemap_read() function. This issue manifests when the kernel processes read operations through the generic file I/O layer, where improper validation of input parameters can lead to catastrophic system behavior. The flaw occurs in the interaction between the iocb->ki_pos value and the iterator count parameter, creating a condition where the kernel's internal loop validation fails to properly terminate execution. The vulnerability was particularly evident when testing with xfstests generic/525, which utilizes loopback NFS mounts with localio optimization, demonstrating how specific filesystem configurations can expose underlying kernel weaknesses.
The technical root cause of this vulnerability stems from insufficient bounds checking within the filemap_read() implementation, which operates as part of the Linux kernel's generic file I/O handling mechanism. When a caller provides an iocb->ki_pos value that approaches the filesystem's upper limit boundary and the iterator count parameter causes an arithmetic overflow beyond that limit, the kernel enters an infinite loop state. This condition violates fundamental security principles by creating a denial of service scenario where legitimate system resources become unavailable due to uncontrolled execution. The flaw aligns with CWE-129, which addresses improper validation of array indices and buffer bounds, and represents a classic example of how integer overflow conditions can be exploited to create infinite loops in kernel space operations. The vulnerability operates at the intersection of multiple kernel subsystems including the file I/O layer, memory management, and filesystem abstraction layers.
The operational impact of CVE-2024-50272 extends beyond simple system performance degradation to potentially complete system compromise through denial of service attacks. When exploited, the infinite loop condition consumes excessive CPU resources and prevents other processes from executing properly, effectively rendering the system unresponsive to legitimate I/O operations. This vulnerability affects systems using loopback NFS mounts with localio optimization, which are common in enterprise environments where network file systems are extensively utilized. The attack surface includes any system that employs the affected kernel version and processes read operations through the filemap subsystem, making it particularly concerning for servers, storage systems, and network infrastructure. The vulnerability can be exploited remotely through network file system operations or locally through direct system calls, providing multiple attack vectors that could be leveraged by malicious actors to disrupt system availability.
Mitigation strategies for CVE-2024-50272 require immediate kernel updates from vendors that include the resolved bounds checking fixes. System administrators should prioritize patching affected systems with the latest kernel releases that contain the specific fix for filemap_read() function bounds validation. Additionally, monitoring systems should be configured to detect unusual CPU utilization patterns that might indicate exploitation attempts. The fix implements proper bounds validation checks that prevent the overflow condition from causing infinite loop behavior, ensuring that read operations properly terminate even when approaching filesystem limits. Organizations should also consider implementing access controls and limiting the scope of file system operations that could trigger this condition. This vulnerability highlights the importance of maintaining current kernel versions and implementing comprehensive security monitoring to detect and respond to similar issues before they can be exploited in production environments. The mitigation approach aligns with ATT&CK technique T1499.004, which addresses network denial of service through resource exhaustion, and emphasizes the critical need for kernel-level security updates in maintaining system integrity.