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CVE Record

CVE-2021-47113: btrfs: abort in rename_exchange if we fail to insert the second ref

In the Linux kernel, the following vulnerability has been resolved: btrfs: abort in rename_exchange if we fail to insert the second ref Error injection stress uncovered a problem where we'd leave a dangling inode ref if we failed during a rename_exchange. This happens because we insert the inode ref for one side of the rename, and then for the other side. If this second inode ref insert fails we'll leave the first one dangling and leave a corrupt file system behind. Fix this by aborting if we did the insert for the first inode ref.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel Btrfs flaw can leave a filesystem corrupted if a rename-exchange operation fails at a specific point. It is mainly a data integrity risk for systems using Btrfs, not a confirmed remote-code-execution issue. No source in the bundle reports active exploitation.

Executive priority

Treat as a targeted reliability and data integrity issue. Prioritize patching where Btrfs supports production data, databases, build systems, or backup repositories. Broader emergency response is not supported by the provided evidence.

Technical view

In Btrfs rename_exchange handling, the kernel inserts inode references for both sides. If the second insert fails after the first succeeds, the first reference can remain dangling, corrupting the filesystem. The fix aborts when the first inode reference was inserted and the second insert fails.

Likely exposure

Exposure is most relevant to Linux systems using Btrfs. The source bundle lists Linux kernel versions and stable fixes, but exact distribution package ranges must be confirmed against vendor advisories.

Exploitation context

The issue was found through error-injection stress testing. The bundle marks KEV as false and provides no evidence of public exploitation or weaponized use.

Researcher notes

The source describes a filesystem-consistency bug in Btrfs rename_exchange error handling. Affected-version semantics in the bundle are incomplete, so researchers should verify exact kernel ranges through upstream stable commits and distribution advisories.

Mitigation direction

  • Identify Linux systems using Btrfs filesystems.
  • Check kernel vendor advisories for CVE-2021-47113 package status.
  • Update to a vendor kernel containing the cited stable fixes.
  • Prioritize systems where Btrfs stores critical or hard-to-restore data.
  • Maintain current backups before kernel or filesystem maintenance.

Validation and detection

  • Inventory kernel versions on Btrfs-backed hosts.
  • Map running kernels to vendor fixed package versions.
  • Check whether cited stable commits are included in custom kernels.
  • Review storage monitoring for Btrfs corruption or transaction errors.
  • Confirm backups and restore procedures for affected systems.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2021-47113 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxcdd1fedf8261cd7a73c0596298902ff4f0f04492, cdd1fedf8261cd7a73c0596298902ff4f0f04492, cdd1fedf8261cd7a73c0596298902ff4f0f04492unaffected
LinuxLinux4.7, 0, 5.10.43, 5.12.10, 5.13affected
Weakness

CWE details

No CWE listed

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