CVE-2021-20261 Race condition in kernel

What is CVE-2021-20261?

CVE-2021-20261 is a medium-severity vulnerability in Linux kernel, published on 11 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A race condition was found in the Linux kernels implementation of the floppy disk drive controller driver software. The impact of this issue is lessened by the fact that the default permissions on the floppy device (/dev/fd0) are restricted to root. If the permissions on the device have changed the impact changes greatly. In the default configuration root (or equivalent) permissions are required to attack this flaw.

Weakness: CWE-362

Which versions are affected by CVE-2021-20261?

It affects 2 products.

Products include Linux kernel, Redhat Enterprise Linux.

How do I fix CVE-2021-20261?

Apply the vendor's patch.

Is CVE-2021-20261 being exploited?

There is no known exploitation of CVE-2021-20261 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-2021-20261, GHSA-8p2q-8rc4-vfp4, UBUNTU-CVE-2021-20261.