# CVE-2026-93050: ipack: ipoctal: fix UAF, null-ptr-deref, and use-after-free in cleanup on remove

CVE-2026-93050 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-93050, released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-93050
- Priority: High
- CVSS: 7.1 (Moderate)
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-93050

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.190-1 | [DEBIAN-CVE-2026-93050](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93050.md) | Sep 23, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-93050](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93050.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-93050](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93050.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-93050](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93050.md) | Sep 23, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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