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.
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.
Published:
2026-09-17
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No remediation available yet.
Tracking
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Advisories
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References
History
Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | ipack: ipoctal: fix UAF, null-ptr-deref, and use-after-free in cleanup on remove | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-17T16:10:40.360Z
Reserved: 2026-09-17T15:57:05.658Z
Link: CVE-2026-93050
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:58.367
Modified: 2026-09-17T17:17:58.367
Link: CVE-2026-93050
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.