CVE-2026-90334: tty: clear cdev pointer after cdev_add() failure

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: tty: clear cdev pointer after cdev_add() failure tty_cdev_add() drops the cdev reference when cdev_add() fails, but leaves driver->cdevs[index] pointing to freed memory. tty_unregister_device() later passes that stale pointer to cdev_del(), causing a use-after-free. Clear the slot after dropping the reference.

Affected products

Linux kernel: 4.3 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/33a44333a9dfda044b0e233399b12ead7f8a90ae
https://git.kernel.org/stable/c/4f6bd79bb7e55095f09bec9b4eb6c09df1306116
https://git.kernel.org/stable/c/5c5a795bf6248fe96f96dd9fd79d66bbb4a92077
https://git.kernel.org/stable/c/6645856f0df3aeecd45519cb611415b4b89c2223
https://git.kernel.org/stable/c/a83fcddf3c75d004f12aa13555bb73da19fb75a9
https://git.kernel.org/stable/c/d331c63570af61ef7aaf516b64a8d6f47518a3a4
https://git.kernel.org/stable/c/e9e64dd02fd68776afda00777591eca0c3984285
https://git.kernel.org/stable/c/fb1de260033c215dba438973d82b48562bdc86bb

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