CVE-2022-50779 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
orangefs: Fix kmemleak in orangefs_prepare_debugfs_help_string()
When insert and remove the orangefs module, then debug_help_string will be leaked:
unreferenced object 0xffff8881652ba000 (size 4096): comm "insmod", pid 1701, jiffies 4294893639 (age 13218.530s) hex dump (first 32 bytes): 43 6c 69 65 6e 74 20 44 65 62 75 67 20 4b 65 79 Client Debug Key 77 6f 72 64 73 20 61 72 65 20 75 6e 6b 6e 6f 77 words are unknow backtrace: [<0000000004e6f8e3>] kmalloc_trace+0x27/0xa0
[<0000000006f75d85>] orangefs_prepare_debugfs_help_string+0x5e/0x480 [orangefs]
[<0000000091270a2a>] _sub_I_65535_1+0x57/0xf70 [crc_itu_t]
[<000000004b1ee1a3>] do_one_initcall+0x87/0x2a0
[<000000001d0614ae>] do_init_module+0xdf/0x320
[<00000000efef068c>] load_module+0x2f98/0x3330
[<000000006533b44d>] __do_sys_finit_module+0x113/0x1b0
[<00000000a0da6f99>] do_syscall_64+0x35/0x80
[<000000007790b19b>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
When remove the module, should always free debug_help_string. Should always free the allocated buffer when change the free_debug_help_string.
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Analysis
by VulDB Data Team • 04/22/2026
The vulnerability described in CVE-2022-50779 represents a memory leak issue within the Linux kernel's Orangefs file system implementation. This flaw manifests when the orangefs kernel module is dynamically inserted and removed from the system, specifically affecting the debugfs subsystem's memory management. The issue is classified as a kmemleak, which occurs when kernel memory allocated through kmalloc is not properly freed, leading to persistent memory consumption that can accumulate over time and potentially impact system stability and performance. The vulnerability demonstrates a classic improper resource management pattern where allocated memory remains unreferenced after module removal.
The technical implementation flaw resides in the orangefs_prepare_debugfs_help_string() function within the Orangefs kernel module. When the module is loaded, this function allocates a 4096-byte memory buffer to store debug help strings, but fails to ensure proper cleanup during module unloading. The memory leak occurs because the debug_help_string buffer is allocated but never freed when the module is removed, creating a persistent memory footprint that can grow with repeated module loading cycles. This pattern violates fundamental kernel memory management principles and demonstrates inadequate error handling in the module's lifecycle management code.
The operational impact of this vulnerability extends beyond simple memory consumption, as it represents a potential denial of service vector that could gradually exhaust system resources. When the orangefs module is repeatedly inserted and removed, each operation creates a memory leak that accumulates over time, potentially leading to system instability or performance degradation. The vulnerability is particularly concerning in environments where kernel modules are frequently loaded and unloaded, such as in containerized environments or systems with dynamic module management. From a security perspective, while this vulnerability does not directly enable privilege escalation or remote code execution, it creates a persistent resource exhaustion condition that could be exploited in conjunction with other vulnerabilities to facilitate system compromise.
Mitigation strategies for this vulnerability involve ensuring proper memory management within the Orangefs kernel module by implementing consistent memory allocation and deallocation patterns. The fix requires modifying the module's unload routine to always free the debug_help_string buffer when the module is removed, regardless of the module's operational state. This approach aligns with security best practices outlined in the Common Weakness Enumeration (CWE) category CWE-404, which addresses improper resource management and memory leaks in kernel code. Additionally, the fix should incorporate defensive programming practices such as checking for null pointers before deallocation and ensuring that all allocated memory paths include corresponding cleanup code. The solution also aligns with the MITRE ATT&CK framework's concept of privilege escalation through resource exhaustion, where persistent memory leaks can contribute to system instability that attackers might exploit to gain unauthorized access or disrupt system operations.