CVE-2023-53391: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53391 is a vulnerability in the Linux kernel related to memory management in the tmpfs filesystem. The issue was discovered and disclosed on September 18, 2025. The vulnerability affects the ramfs-based tmpfs implementation, specifically in how it handles the kill_sb method (NVD).

The vulnerability stems from improper memory management in the tmpfs filesystem implementation. Specifically, when the ramfs-based tmpfs uses ramfsinitfscontext() for the initfscontext method, it allocates fc->sfsinfo but fails to properly free it, resulting in a memory leak. The issue requires using ramfskillsb() for the killsb method of ramfs-based tmpfs to properly free allocated memory (Ubuntu).

The primary impact of this vulnerability is a memory leak in the Linux kernel's tmpfs filesystem implementation. While memory leaks can potentially lead to system resource exhaustion over time, this particular issue appears to have limited direct security implications (NVD).

Multiple Linux distributions have released patches to address this vulnerability. Ubuntu has fixed the issue in various kernel versions including linux-kvm (5.15.0-1044.49), linux-azure (5.15.0-1049.56), and linux-gcp (5.15.0-1044.52). The fix involves implementing proper memory cleanup by using ramfskillsb() for the kill_sb method (Ubuntu).