CVE-2022-2978 in Linux
Summary
by MITRE • 08/24/2022
A flaw use after free in the Linux kernel NILFS file system was found in the way user triggers function security_inode_alloc to fail with following call to function nilfs_mdt_destroy. A local user could use this flaw to crash the system or potentially escalate their privileges on the system.
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Analysis
by VulDB Data Team • 05/28/2026
The vulnerability identified as CVE-2022-2978 represents a critical use-after-free flaw within the Linux kernel's NILFS (New Implementation of LogFS) file system implementation. This issue manifests when specific error conditions occur during the allocation and destruction of inode objects, creating a scenario where freed memory locations can be accessed after they have been deallocated. The flaw specifically occurs during the interaction between the security_inode_alloc function and the nilfs_mdt_destroy function, where improper memory management leads to a dangerous state that can be exploited by local attackers.
The technical root cause of this vulnerability stems from inadequate memory management practices within the NILFS file system driver. When security_inode_alloc fails to allocate an inode structure properly, the subsequent call to nilfs_mdt_destroy does not properly handle the cleanup process, leaving behind dangling pointers or references to memory that has already been freed. This memory corruption scenario creates opportunities for attackers to manipulate the system's memory layout and potentially execute arbitrary code with elevated privileges. The vulnerability falls under the CWE-416 category of Use After Free, which is classified as a critical memory safety issue that can lead to privilege escalation or system crashes.
From an operational perspective, this flaw poses significant risks to Linux systems that utilize the NILFS file system, particularly those running in multi-user environments where local privilege escalation could provide attackers with root access to the system. The vulnerability requires local system access to exploit, but once triggered, it can result in either a denial of service through system crashes or more severe privilege escalation attacks that allow attackers to gain administrative control over affected systems. The impact is particularly concerning because it affects the core kernel functionality and can potentially compromise the entire system integrity.
The exploitation of this vulnerability typically involves a local attacker who can trigger the specific error path that leads to the use-after-free condition. Attackers may leverage this flaw by performing operations that cause security_inode_alloc to fail while simultaneously initiating the cleanup process through nilfs_mdt_destroy. The potential for privilege escalation exists because the memory corruption can be manipulated to redirect execution flow or overwrite critical kernel data structures. Organizations should consider this vulnerability in their security assessments and prioritize patching efforts, especially for systems where the NILFS file system is actively used. The flaw also highlights the importance of proper memory management practices in kernel space code and demonstrates the need for comprehensive testing of error handling paths in file system implementations. System administrators should monitor for any signs of exploitation attempts and ensure that all kernel updates are applied promptly to mitigate the risk of this vulnerability being exploited in the wild.
This vulnerability aligns with several ATT&CK techniques including privilege escalation through kernel exploits and system compromise via denial of service attacks. The presence of this flaw in widely deployed Linux distributions makes it a significant concern for enterprise security teams and system administrators who must maintain robust patch management processes to protect against such kernel-level exploits.