CVE-2026-90135 net: add missing ref_tracker_dir_exit() to alloc_netdev_mqs()
A use-after-free in the Linux kernel network subsystem can cause a crash when reading debug files if device allocation fails.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90135?
CVE-2026-90135 is an use after free vulnerability in Linux, published on 17 Sep 2026. 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: add missing ref_tracker_dir_exit() to alloc_netdev_mqs()
sashiko is reporting that trying to read /sys/kernel/debug/ref_tracker/* causes use-afer-free crash when either alloc_percpu() or dev_addr_init() in alloc_netdev_mqs() failed, for commit 4d92b95ff2f9 ("net: add net device refcount tracker infrastructure") added ref_tracker_dir_exit() to only free_netdev() path.
Which versions are affected by CVE-2026-90135?
How do I fix CVE-2026-90135?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-90135 being exploited?
There is no known exploitation of CVE-2026-90135 in the wild and no public exploit code.
Sources
Also known as AZL-102833, BELL-CVE-2026-90135, DEBIAN-CVE-2026-90135, GHSA-j74m-jp6j-hqp6, UBUNTU-CVE-2026-90135.