CVE-2020-27784 Use after free in kernel

What is CVE-2020-27784?

CVE-2020-27784 is a medium-severity use after free vulnerability in Linux kernel, published on 1 Sep 2022. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A vulnerability was found in the Linux kernel, where accessing a deallocated instance in printer_ioctl() printer_ioctl() tries to access of a printer_dev instance. However, use-after-free arises because it had been freed by gprinter_free().

Weakness: CWE-416, CWE-201

Which versions are affected by CVE-2020-27784?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2020-27784?

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-2020-27784 being exploited?

There is no known exploitation of CVE-2020-27784 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 DEBIAN-CVE-2020-27784, GHSA-wmh9-52hx-xj2c, UBUNTU-CVE-2020-27784.