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NVD / CVE Program· CNA Linux

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

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: 0.19% (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 077259f5e777c3c8821f6b41dee709fcda27306b, 1e97743fd180981bef5f01402342bb54bf1c6366, 4.14.233.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 077259f5e777c3c8821f6b41dee709fcda27306b, 1e97743fd180981bef5f01402342bb54bf1c6366, 4.14.233 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: 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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 29, 2024
Updated
Aug 5, 2026
EPSS
0.1% · 9th percentile

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 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
7.1
1.6 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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

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Follow CVE-2021-47055

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  • when the record is updated (including a fixed version)
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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 kernel4.4.233 and later · before 4.4.269
  • linux linux kernel4.9.233 and later · before 4.9.269
  • linux linux kernel4.14.194 and later · before 4.14.233
  • linux linux kernel4.19.139 and later · before 4.19.191
  • linux linux kernel5.4.58 and later · before 5.4.119
  • linux linux kernel5.9 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

    • 36a8b2f49235e63ab3f901fe12e1b6732f075c2e, eb3d82abc335624a5e8ecfb75aba0b684e2dc4db, 5.9affected
    • 1c9f9125892a43901438bf704ada6b7019e2a884 and later · before f4d28d8b9b0e7c4ae04214b8d7e0b0466ec6bcafaffected · git
    • 583d42400532fbd6228b0254d7c732b771e4750d and later · before 9625b00cac6630479c0ff4b9fafa88bee636e1f0affected · git
    • 389c74c218d3b182e9cd767e98cee0e0fd0dabaa and later · before f73b29819c6314c0ba8b7d5892dfb03487424beeaffected · git
    • ab1a602a9cea98aa37b2e6851b168d2a2633a58d and later · before 75ed985bd6c8ac1d4e673e93ea9d96c9908c1d37affected · git
    • 9a53e8bd59d9f070505e51d3fd19606a270e6b93 and later · before 5880afefe0cb9b2d5e801816acd58bfe91a96981affected · git
    • f7e6b19bc76471ba03725fe58e0c218a3d6266c3 and later · before 7b6552719c0ccbbea29dde4be141da54fdb5877eaffected · git
    • f7e6b19bc76471ba03725fe58e0c218a3d6266c3 and later · before 077259f5e777c3c8821f6b41dee709fcda27306baffected · git
    • f7e6b19bc76471ba03725fe58e0c218a3d6266c3 and later · before a08799d3e8c8088640956237c183f83463c39668affected · git
    • f7e6b19bc76471ba03725fe58e0c218a3d6266c3 and later · before 1e97743fd180981bef5f01402342bb54bf1c6366affected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8bpftoolbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernelbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-abi-stablelistsbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-corebefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-cross-headersbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-debugbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-debug-corebefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-debug-develbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-debug-modulesbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-debug-modules-extrabefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-develbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-docbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-headersbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-modulesbefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-modules-extrabefore 4.18.0-553.5.1.el8_104.18.0-553.5.1.el8_10
AlmaLinux:8kernel-rtbefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-corebefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-debugbefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-debug-corebefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-debug-develbefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-debug-kvmbefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-debug-modulesbefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-debug-modules-extrabefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10
AlmaLinux:8kernel-rt-develbefore 4.18.0-553.5.1.rt7.346.el8_104.18.0-553.5.1.rt7.346.el8_10

+65

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-2021-47020Feb 29, 2024 · soundwire: stream: fix memory leak in stream config error path
    22Monitor
  • ← EarlierCVE-2021-47054Feb 29, 2024 · bus: qcom: Put child node before return
    22Monitor
  • Later →CVE-2021-47056Feb 29, 2024 · crypto: qat - ADF_STATUS_PF_RUNNING should be set after adf_dev_init
    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 Linux077259f5e777c3c8821f6b41dee709fcda27306bVendor (CNA)
Linux Linux1e97743fd180981bef5f01402342bb54bf1c6366Vendor (CNA)
Linux Linux4.14.233Vendor (CNA)
Linux Linux4.19.191Vendor (CNA)
Linux Linux4.4.269Vendor (CNA)
Linux Linux4.9.269Vendor (CNA)
Linux Linux5.4.119Vendor (CNA)
Linux Linux5.8Vendor (CNA)
Linux Linux5.9Vendor (CNA)
Linux Linux5880afefe0cb9b2d5e801816acd58bfe91a96981Vendor (CNA)
Linux Linux75ed985bd6c8ac1d4e673e93ea9d96c9908c1d37Vendor (CNA)
Linux Linux7b6552719c0ccbbea29dde4be141da54fdb5877eVendor (CNA)
Linux Linux9625b00cac6630479c0ff4b9fafa88bee636e1f0Vendor (CNA)
Linux Linuxa08799d3e8c8088640956237c183f83463c39668Vendor (CNA)
Linux Linuxf4d28d8b9b0e7c4ae04214b8d7e0b0466ec6bcafVendor (CNA)
Linux Linuxf73b29819c6314c0ba8b7d5892dfb03487424beeVendor (CNA)
almalinux:bpftool4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-abi-stablelists4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-core4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-cross-headers4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-core4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-devel4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-debug-modules-extra4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-devel4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-doc4.18.0-553.5.1.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux5.10.38-1 · Debian:12Package registry (OSV)
red hat:bpftool0:4.18.0-553.5.1.el8_10 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)

+13

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)

CWE-667 · Improper Locking

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.

Change log

  1. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records