CVE-2021-47055 mtd: require write permissions for locking and badblock ioctls

What is CVE-2021-47055?

CVE-2021-47055 is a high-severity missing authorization vulnerability in Linux kernel, published on 29 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:

mtd: require write permissions for locking and badblock ioctls

MEMLOCK, MEMUNLOCK and OTPLOCK modify protection bits. Thus require write permission. Depending on the hardware MEMLOCK might even be write-once, e.g. for SPI-NOR flashes with their WP# tied to GND. OTPLOCK is always write-once.

MEMSETBADBLOCK modifies the bad block table.

Weakness: CWE-667

Which versions are affected by CVE-2021-47055?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47055?

Apply the vendor's patch.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2021-47055 being exploited?

There is no known exploitation of CVE-2021-47055 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-2021-47055, GHSA-x2mc-jwgp-h2fq, UBUNTU-CVE-2021-47055.