CVE-2022-49926 net: dsa: Fix possible memory leaks in dsa_loop_init()
A memory leak in the Linux kernel DSA loop driver can lead to resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49926?
CVE-2022-49926 is a medium-severity memory corruption vulnerability in Linux kernel, published on 1 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: dsa: Fix possible memory leaks in dsa_loop_init()
kmemleak reported memory leaks in dsa_loop_init():
kmemleak: 12 new suspected memory leaks
unreferenced object 0xffff8880138ce000 (size 2048): comm "modprobe", pid 390, jiffies 4295040478 (age 238.976s) backtrace: [<000000006a94f1d5>] kmalloc_trace+0x26/0x60 [<00000000a9c44622>] phy_device_create+0x5d/0x970 [<00000000d0ee2afc>] get_phy_device+0xf3/0x2b0 [<00000000dca0c71f>] __fixed_phy_register.part.0+0x92/0x4e0 [<000000008a834798>] fixed_phy_register+0x84/0xb0 [<0000000055223fcb>] dsa_loop_init+0xa9/0x116 [dsa_loop] ...
There are two reasons for memleak in dsa_loop_init().
First, fixed_phy_register() create and register phy_device:
fixed_phy_register() get_phy_device() phy_device_create() # freed by phy_device_free() phy_device_register() # freed by phy_device_remove()
But fixed_phy_unregister() only calls phy_device_remove(). So the memory allocated in phy_device_create() is leaked.
Second, when mdio_driver_register() fail in dsa_loop_init(), it just returns and there is no cleanup for phydevs.
Fix the problems by catching the error of mdio_driver_register() in dsa_loop_init(), then calling both fixed_phy_unregister() and phy_device_free() to release phydevs. Also add a function for phydevs cleanup to avoid duplacate.
Weakness: CWE-401
Which versions are affected by CVE-2022-49926?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49926?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2022-49926 being exploited?
There is no known exploitation of CVE-2022-49926 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49926, GHSA-262g-44pp-38c2, UBUNTU-CVE-2022-49926.