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CVE-2021-47433· NVD / CVE Program· CNA Linux

btrfs: fix abort logic in btrfs_replace_file_extents

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: 0.58% (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 0e309e1152fc34ef75991d9d69b165dbf75bf26c, 0e32a2b85c7d92ece86c17dfef390c5ed79c6378, 4afb912f439c4bc4e6a4f3e7547f2e69e354108f.
  • Severity is disputed: the assigning authority (CNA) scores it 8.1, NVD 5.5.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0e309e1152fc34ef75991d9d69b165dbf75bf26c, 0e32a2b85c7d92ece86c17dfef390c5ed79c6378, 4afb912f439c4bc4e6a4f3e7547f2e69e354108f 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: btrfs: fix abort logic in btrfs_replace_file_extents Error injection testing uncovered a case where we'd end up with a corrupt file system with a missing extent in the middle of a file. This occurs because the if statement to decide if we should abort is wrong. The only way we would abort in this case is if we got a ret != -EOPNOTSUPP and we called from the file clone code. However the prealloc code uses this path too. Instead we need to abort if there is an error, and the only error we _don't_ abort on is -EOPNOTSUPP and only if we came from the clone file code.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 22, 2024
Updated
Aug 5, 2026
EPSS
0.5% · 46th 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 · 0.5%

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
8.1
2.6 point gap

CVSS:3.1/AV:N/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

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

Follow CVE-2021-47433

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 kernelbefore 5.10.75
  • linux linux kernel5.11 and later · before 5.14.14
  • linux linux kernel5.15

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

    • 5.10affected
    • 8fccebfa534c7984864394fa03608305e4929aae and later · before 0e32a2b85c7d92ece86c17dfef390c5ed79c6378affected · git
    • 8fccebfa534c7984864394fa03608305e4929aae and later · before 0e309e1152fc34ef75991d9d69b165dbf75bf26caffected · git
    • 8fccebfa534c7984864394fa03608305e4929aae and later · before 4afb912f439c4bc4e6a4f3e7547f2e69e354108faffected · git
    • before 5.10not affected · semver
    • 5.10.75 and later · up to and including 5.10.*not affected · semver
    • 5.14.14 and later · up to and including 5.14.*not affected · semver
    • 5.15 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
Debian:12linuxbefore 5.14.16-15.14.16-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • 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
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2023-52879May 21, 2024 · tracing: Have trace_event_file have ref counters
    22Monitor
  • ← EarlierCVE-2021-47316May 21, 2024 · nfsd: fix NULL dereference in nfs3svc_encode_getaclres
    22Monitor
  • Later →CVE-2021-47434May 22, 2024 · xhci: Fix command ring pointer corruption while aborting a command
    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 Linux0e309e1152fc34ef75991d9d69b165dbf75bf26cVendor (CNA)
Linux Linux0e32a2b85c7d92ece86c17dfef390c5ed79c6378Vendor (CNA)
Linux Linux4afb912f439c4bc4e6a4f3e7547f2e69e354108fVendor (CNA)
debian:linux5.14.16-1 · Debian:12Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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 (2 more)

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

All records