CVE-2026-93050 ipack: ipoctal: fix UAF, null-ptr-deref, and use-after-free in cleanup on remove
Local attackers can trigger use-after-free and null pointer dereference in the ipoctal driver during device removal, potentially leading to privilege escalation or system crash.
- 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-2026-93050?
CVE-2026-93050 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:
ipack: ipoctal: fix UAF, null-ptr-deref, and use-after-free in cleanup on remove
Three issues arise when the device is removed while a tty session is still active:
1. UAF of struct ipoctal: the remove callback frees ipoctal via kfree() while tty ops may still access it. Fix by introducing kref-based lifetime management — kref is taken in install() when a tty is opened and released in cleanup() when the tty is finally destroyed; remove() uses kref_put() instead of kfree().
2. NULL dereference in ipoctal_write_tty(): __ipoctal_remove() frees xmit_buf via tty_port_free_xmit_buf() while a userspace process may still hold the tty fd and call write(). Fix by checking for NULL xmit_buf in ipoctal_write_tty().
3. UAF in ipoctal_cleanup(): ipack_put_carrier(ipoctal->dev) dereferences ipoctal->dev after the ipack_device has been freed by ipack_device_del(). Fix by caching ipoctal->carrier_owner during probe() and calling module_put() on the cached pointer directly in cleanup(), avoiding any access to ipoctal->dev.
Also introduce a "removed" flag in struct ipoctal, set at the start of __ipoctal_remove(), and checked in every tty op that accesses hardware resources (port_activate, write_tty, set_termios, hangup, shutdown). This prevents page faults when devm_ioremap() regions are unmapped after remove() returns.
Which versions are affected by CVE-2026-93050?
How do I fix CVE-2026-93050?
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-2026-93050 being exploited?
There is no known exploitation of CVE-2026-93050 in the wild and no public exploit code.
Sources
Also known as AZL-102318, BELL-CVE-2026-93050, DEBIAN-CVE-2026-93050, GHSA-7qcc-hqrm-qfrj, UBUNTU-CVE-2026-93050.