CVE-2022-50779

Vulnerability

CVE-2022-50779 describes a memory leak in the Linux kernel's OrangeFS (orangefs) filesystem module. The function orangefs_prepare_debugfs_help_string() allocates a buffer (debug_help_string) using kmalloc_trace but fails to free it when the module is removed. This results in a kernel memory leak that can be observed via kmemleak, as shown in the kernel commit references [1][2][3][4].

Exploitation

An attacker with the ability to load and unload the orangefs kernel module (typically requiring root privileges) can trigger the leak repeatedly. Each module insertion allocates a new 4096-byte buffer is allocated and never freed, gradually consuming kernel memory. No special network access or user interaction is needed beyond module load/unload operations.

Impact

Repeated module insertions and removals will exhaust kernel memory, potentially leading to system instability or denial of service (DoS). The leak is limited to the size of the allocated buffer (4 KB per cycle), but sustained exploitation can degrade system performance or cause out-of-memory conditions.

Mitigation

The fix is included in Linux kernel stable updates. The patch ensures that debug_help_string is freed when the module is removed, preventing the memory leak. Users should apply the latest kernel updates from their distribution or compile a patched kernel from the stable tree containing the commit referenced in [1][2][3][4].