CVE-2022-50811: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-50811 is a resource leak vulnerability in the Linux kernel's EROFS (Enhanced Read-Only File System) subsystem. The flaw occurs when z_erofs_get_extent_compressedlen() fails without performing the required unmap operation, resulting in meta buffer leaks. It affects Linux kernel versions starting from 5.13 up to the patched releases (6.0.16, 6.1.2, and 6.2). The vulnerability was published on December 30, 2025, and carries an EPSS score of approximately 0.017% (Feedly). No CVSS base score has been assigned by the assigner.

The root cause is a missing unmap call in the EROFS compressed extent handling code path when z_erofs_get_extent_compressedlen() returns an error (CWE-401: Missing Release of Memory after Effective Lifetime). When this function fails, the code path exits without unmapping previously mapped meta buffers, causing those buffers to be permanently leaked. The vulnerability is local in nature, requiring a process to interact with an EROFS-mounted filesystem to trigger the error path. Fixes were applied across three stable kernel branches via commits 091a8ca572a2, 373b6f350aec, and d5d188b8f8b3 (Kernel Git).

Successful triggering of this vulnerability results in kernel memory (meta buffers) being leaked, gradually degrading system memory availability. The primary impact is on availability — repeated triggering could exhaust kernel memory resources, potentially leading to system instability or denial of service. Confidentiality and integrity are not directly affected, as the flaw does not expose data to unauthorized parties or allow memory corruption.

The vulnerability is fixed in Linux kernel stable releases 6.0.16, 6.1.2, and 6.2. Users should update to one of these patched versions or apply the relevant stable-tree commits (091a8ca572a2, 373b6f350aec, d5d188b8f8b3) (Kernel Git). As a workaround, systems that do not require EROFS filesystem support can unload or disable the erofs kernel module to eliminate exposure.