CVE-2021-47018 powerpc/64: Fix the definition of the fixmap area

What is CVE-2021-47018?

CVE-2021-47018 is a medium-severity vulnerability in Linux kernel, published on 28 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:

powerpc/64: Fix the definition of the fixmap area

At the time being, the fixmap area is defined at the top of the address space or just below KASAN.

This definition is not valid for PPC64.

For PPC64, use the top of the I/O space.

Because of circular dependencies, it is not possible to include asm/fixmap.h in asm/book3s/64/pgtable.h , so define a fixed size AREA at the top of the I/O space for fixmap and ensure during build that the size is big enough.

Which versions are affected by CVE-2021-47018?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47018?

Apply the vendor's patch.

Is CVE-2021-47018 being exploited?

There is no known exploitation of CVE-2021-47018 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-2021-47018, GHSA-p768-cw2x-34vr, UBUNTU-CVE-2021-47018.