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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.23% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 4b9fb2c9039a206d37f215936a4d5bee7b1bf9cd, 9ccba66d4d2aff9a3909aa77d57ea8b7cc166f3c, a84df7c80bdac598d6ac9268ae578da6928883e8.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 4b9fb2c9039a206d37f215936a4d5bee7b1bf9cd, 9ccba66d4d2aff9a3909aa77d57ea8b7cc166f3c, a84df7c80bdac598d6ac9268ae578da6928883e8 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 28, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 15th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.5 and later · before 5.10.37
  • linux linux kernel5.11 and later · before 5.11.21
  • linux linux kernel5.12 and later · before 5.12.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.5affected
    • 265c3491c4bc8d40587996d6ee2f447a7ccfb4f3 and later · before 4b9fb2c9039a206d37f215936a4d5bee7b1bf9cdaffected · git
    • 265c3491c4bc8d40587996d6ee2f447a7ccfb4f3 and later · before abb07dc5e8b61ab7b1dde20dd73aa01a3aeb183faffected · git
    • 265c3491c4bc8d40587996d6ee2f447a7ccfb4f3 and later · before a84df7c80bdac598d6ac9268ae578da6928883e8affected · git
    • 265c3491c4bc8d40587996d6ee2f447a7ccfb4f3 and later · before 9ccba66d4d2aff9a3909aa77d57ea8b7cc166f3caffected · git
    • before 5.5not affected · semver
    • 5.10.37 and later · up to and including 5.10.*not affected · semver
    • 5.11.21 and later · up to and including 5.11.*not affected · semver
    • 5.12.4 and later · up to and including 5.12.*not affected · semver
    • 5.13 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8bpftoolbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-docbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-headersbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-modulesbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-modules-extrabefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-toolsbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-tools-libsbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-tools-libs-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-zfcpdumpbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-zfcpdump-corebefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-zfcpdump-develbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-zfcpdump-modulesbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8kernel-zfcpdump-modules-extrabefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10
AlmaLinux:8perfbefore 4.18.0-553.16.1.el8_104.18.0-553.16.1.el8_10

+38

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47015Feb 28, 2024 · bnxt_en: Fix RX consumer index logic in the error path.
    22Monitor
  • ← EarlierCVE-2021-47017Feb 28, 2024 · ath10k: Fix a use after free in ath10k_htc_send_bundle
    31Monitor
  • Later →CVE-2021-47019Feb 28, 2024 · mt76: mt7921: fix possible invalid register access
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux4b9fb2c9039a206d37f215936a4d5bee7b1bf9cdVendor (CNA)
Linux Linux9ccba66d4d2aff9a3909aa77d57ea8b7cc166f3cVendor (CNA)
Linux Linuxa84df7c80bdac598d6ac9268ae578da6928883e8Vendor (CNA)
Linux Linuxabb07dc5e8b61ab7b1dde20dd73aa01a3aeb183fVendor (CNA)
almalinux:bpftool4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-core4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc4.18.0-553.16.1.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux5.10.38-1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:bpftool-debuginfo0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-abi-stablelists0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-core0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-core0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-debuginfo0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-devel0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-modules0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debug-modules-extra0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:kernel-debuginfo0:4.18.0-553.16.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
rocky linux:kernel0:4.18.0-553.16.1.el8_10 · Rocky Linux:8Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records