CVE-2021-46905 net: hso: fix NULL-deref on disconnect regression

What is CVE-2021-46905?

CVE-2021-46905 is a medium-severity vulnerability in Linux kernel, published on 25 Feb 2024. 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:

net: hso: fix NULL-deref on disconnect regression

Commit 8a12f8836145 ("net: hso: fix null-ptr-deref during tty device unregistration") fixed the racy minor allocation reported by syzbot, but introduced an unconditional NULL-pointer dereference on every disconnect instead.

Specifically, the serial device table must no longer be accessed after the minor has been released by hso_serial_tty_unregister().

Weakness: CWE-476

Which versions are affected by CVE-2021-46905?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-46905?

Apply the vendor's patch.

Is CVE-2021-46905 being exploited?

There is no known exploitation of CVE-2021-46905 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-q52q-f54c-xmvp, UBUNTU-CVE-2021-46905.