CVE-2022-50772 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
netdevsim: fix memory leak in nsim_bus_dev_new()
If device_register() failed in nsim_bus_dev_new(), the value of reference in nsim_bus_dev->dev is 1. obj->name in nsim_bus_dev->dev will not be released.
unreferenced object 0xffff88810352c480 (size 16): comm "echo", pid 5691, jiffies 4294945921 (age 133.270s) hex dump (first 16 bytes): 6e 65 74 64 65 76 73 69 6d 31 00 00 00 00 00 00 netdevsim1...... backtrace: [<000000005e2e5e26>] __kmalloc_node_track_caller+0x3a/0xb0
[<0000000094ca4fc8>] kvasprintf+0xc3/0x160
[<00000000aad09bcc>] kvasprintf_const+0x55/0x180
[<000000009bac868d>] kobject_set_name_vargs+0x56/0x150
[<000000007c1a5d70>] dev_set_name+0xbb/0xf0
[<00000000ad0d126b>] device_add+0x1f8/0x1cb0
[<00000000c222ae24>] new_device_store+0x3b6/0x5e0
[<0000000043593421>] bus_attr_store+0x72/0xa0
[<00000000cbb1833a>] sysfs_kf_write+0x106/0x160
[<00000000d0dedb8a>] kernfs_fop_write_iter+0x3a8/0x5a0
[<00000000770b66e2>] vfs_write+0x8f0/0xc80
[<0000000078bb39be>] ksys_write+0x106/0x210
[<00000000005e55a4>] do_syscall_64+0x35/0x80
[<00000000eaa40bbc>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
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Analysis
by VulDB Data Team • 04/21/2026
The vulnerability identified as CVE-2022-50772 resides within the Linux kernel's netdevsim subsystem, specifically in the nsim_bus_dev_new() function where a memory leak occurs under certain failure conditions. This issue represents a classic memory management flaw that can lead to resource exhaustion over time, particularly affecting systems that frequently interact with virtual network devices. The vulnerability is classified as a memory leak according to CWE-401, which deals with the improper management of memory resources. The netdevsim module is designed to simulate network devices for testing purposes, but the improper handling of object references during device registration creates a persistent memory footprint that accumulates with repeated operations.
The technical flaw manifests when device_register() fails within the nsim_bus_dev_new() function, leaving the reference count of nsim_bus_dev->dev at a value of 1 while the obj->name within nsim_bus_dev->dev remains unreleased. This creates an unreferenced kernel object that persists in memory, as evidenced by the memory dump showing the object at address 0xffff88810352c480 with size 16 containing the string "netdevsim1". The object's backtrace reveals the execution path that led to its allocation through kvasprintf and kobject_set_name_vargs functions, ultimately being created during device_add operations in the kernel's device model subsystem. This pattern aligns with ATT&CK technique T1490 for resource exhaustion, where improper resource management leads to system instability.
The operational impact of this vulnerability extends beyond simple memory consumption, as it can contribute to system performance degradation and potential denial of service conditions. When systems repeatedly attempt to register network devices through netdevsim, each failed registration leaves behind a memory leak that compounds over time, eventually consuming significant portions of available kernel memory. The vulnerability affects systems running kernel versions that include the netdevsim module, particularly those utilizing virtualization environments or testing frameworks that rely on simulated network devices. The memory leak can be triggered through various kernel interfaces, including sysfs operations that write to device attributes, making it accessible through standard device management pathways.
Mitigation strategies for CVE-2022-50772 involve applying the official kernel patch that corrects the reference counting and memory release logic in the nsim_bus_dev_new() function. System administrators should ensure their kernels are updated to versions that contain the fix, typically kernel versions 5.19 and later where the vulnerability was resolved. The patch ensures proper cleanup of object names and reference counts even when device registration fails, preventing the accumulation of unreferenced kernel objects. Additionally, monitoring systems for memory usage patterns and implementing automated alerts for unusual memory consumption can help detect exploitation attempts. Organizations should also consider restricting access to netdevsim interfaces where possible, particularly in production environments, and implement proper resource limits for processes that might interact with virtual network device interfaces. The fix addresses the core issue by ensuring that when device_register() fails, the associated kernel object cleanup occurs properly, preventing the accumulation of memory leaks that could eventually lead to system instability or resource exhaustion attacks.