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Fencer Vulns
medium 5.5

CVE-2021-47018 json

powerpc/64: Fix the definition of the fixmap area

published 2024-02-28 2 y ago modified 2026-06-17 4 mo ago also EUVD-2021-33666

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 5.10.37, 5.11.21, 5.12.4, 5.13
  • linux Debian 14, Debian 13, Debian 12 5.10.38-1

debian advisories DEBIAN-CVE-2021-47018

  • kernel RHEL 8 4.18.0-553.16.1.el8_10
  • perf RHEL 8 4.18.0-553.16.1.el8_10
  • bpftool RHEL 8 4.18.0-553.16.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.16.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.16.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.16.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.16.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.16.1.el8_10

red hat advisories RHSA-2024:5101

  • kernel AlmaLinux 8 4.18.0-553.16.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.16.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.16.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.16.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.16.1.el8_10

almalinux advisories ALSA-2024:5101

  • kernel Rocky Linux 8 4.18.0-553.16.1.el8_10.cloud.0.1
  • kernel Rocky Linux 8 4.18.0-553.16.1.el8_10

rocky linux advisories RXSA-2024:5101RLSA-2024:5101

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-47018 updated cvss 3.2

kernel: ensure definition of the fixmap area is in a limit

  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.16.1.el8_10, kernel 4.18.0-553.16.1.el8_10, bpftool 4.18.0-553.16.1.el8_10, kernel-core 4.18.0-553.16.1.el8_10, kernel-tools 4.18.0-553.16.1.el8_10, python3-perf 4.18.0-553.16.1.el8_10, +15 more Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.16.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.16.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.16.1.el8_10
    fixed: vendor fix RHSA-2024:5101
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +6 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.