CVE-2026-97544 in Linux
Summary
by MITRE • 09/25/2026
In the Linux kernel, the following vulnerability has been resolved:
xfs: don't leak dqacct if rhashtable insertion fails
LOLLM observes that xqcheck_mod_live_ino_dqtrx doesn't free the newly allocated dqa object if rhashtable insertion fails. Fix this leak.
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Analysis
by VulDB Data Team • 09/25/2026
The Linux kernel's XFS filesystem implementation contains a resource management flaw within its disk quota accounting subsystem, specifically in the function responsible for checking and modifying live inode quota transactions. This vulnerability arises from an improper error handling path where memory allocated for a dqa object is not released if the subsequent insertion into the rhashtable fails. The root cause lies in the failure to invoke the appropriate deallocation routine when the hash table operation encounters an error condition, leading to a classic resource leak scenario that persists across system uptime until reboot or manual intervention via administrative tools.
From a technical perspective, this issue is categorized under CWE-401, which describes missing release of memory after effective allocation. The rhashtable mechanism in the Linux kernel provides efficient hash-based data structures for managing dynamic collections of objects. When xqcheck_mod_live_ino_dqtrx attempts to insert a newly allocated dqa object into this structure and encounters an insertion failure due to constraints such as table fullness or concurrency issues, it returns without freeing the previously allocated memory. This results in a gradual accumulation of unreleased kernel heap memory over time, particularly on systems with high inode turnover rates where quota accounting is actively managed for numerous files.
The operational impact of this vulnerability manifests primarily through progressive memory exhaustion within the kernel space. While individual leaks may appear negligible initially, sustained operation under heavy file system activity can lead to significant degradation in overall system performance due to increased pressure on the kernel's memory allocator. In severe cases, particularly on resource-constrained systems or those running long-running services with extensive disk quota usage, this leak could contribute to out-of-memory conditions affecting critical processes. Although direct remote code execution is not implied by this specific flaw, the potential for denial of service through resource exhaustion remains a valid concern aligned with ATT&CK technique T1496, which covers Resource Hijacking via environmental effects like memory consumption.
Mitigation strategies should focus on both immediate patching and long-term architectural improvements. The primary remediation involves applying the upstream Linux kernel fix that ensures proper cleanup of allocated resources in error paths within the XFS quota accounting code. System administrators must ensure their systems are updated to include this specific correction, typically available through standard distribution security updates for affected kernel versions. Additionally, organizations should implement monitoring solutions capable of detecting abnormal growth in kernel memory usage patterns associated with filesystem operations. Regular auditing of disk quota configurations and limiting excessive inode creation rates can further reduce the frequency of triggering conditions that expose this vulnerability path. Developers maintaining custom XFS extensions or related tools should review their error handling logic to ensure all allocated resources are properly freed regardless of operation success, adhering strictly to defensive programming principles that prevent similar leaks in other subsystems.