# 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.

- **Severity:** Not scored
- **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:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102318, BELL-CVE-2026-93050, DEBIAN-CVE-2026-93050, GHSA-7qcc-hqrm-qfrj, UBUNTU-CVE-2026-93050

## 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.

## Is CVE-2026-93050 being exploited?

There is no known exploitation of CVE-2026-93050 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93050 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-93050 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-93050/ (Markdown: https://insights.sbomify.com/CVE-2026-93050/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93050
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93050
- OSV: https://osv.dev/vulnerability/CVE-2026-93050

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93050/
Summaries are generated and may contain mistakes; the official description above is the record.