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CVE Record

CVE-2022-49761: btrfs: always report error in run_one_delayed_ref()

In the Linux kernel, the following vulnerability has been resolved: btrfs: always report error in run_one_delayed_ref() Currently we have a btrfs_debug() for run_one_delayed_ref() failure, but if end users hit such problem, there will be no chance that btrfs_debug() is enabled. This can lead to very little useful info for debugging. This patch will: - Add extra info for error reporting Including: * logical bytenr * num_bytes * type * action * ref_mod - Replace the btrfs_debug() with btrfs_err() - Move the error reporting into run_one_delayed_ref() This is to avoid use-after-free, the @node can be freed in the caller. This error should only be triggered at most once. As if run_one_delayed_ref() failed, we trigger the error message, then causing the call chain to error out: btrfs_run_delayed_refs() `- btrfs_run_delayed_refs() `- btrfs_run_delayed_refs_for_head() `- run_one_delayed_ref() And we will abort the current transaction in btrfs_run_delayed_refs(). If we have to run delayed refs for the abort transaction, run_one_delayed_ref() will just cleanup the refs and do nothing, thus no new error messages would be output.

HighCVSS 7.8Not KEV-listedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2022-49761 is a Linux kernel Btrfs flaw tied to delayed reference error handling. The CVSS score is high because successful local exploitation could affect confidentiality, integrity, and availability. The source bundle does not show internet-remote exploitation or active abuse.

Executive priority

Treat as a high-priority patching item for Linux fleets using Btrfs, especially shared systems with local users. It is not presented as remotely exploitable or actively exploited in the supplied sources.

Technical view

The issue is in Btrfs run_one_delayed_ref() error handling. The upstream fix moves reporting into run_one_delayed_ref(), replaces debug logging with error logging, adds context fields, and avoids using a node after it may be freed. The CVE maps this to CWE-416.

Likely exposure

Exposure is most relevant to Linux systems using Btrfs on affected kernel versions or vendor builds that have not incorporated the referenced stable fixes. Exact distribution exposure must be confirmed against vendor kernel advisories.

Exploitation context

The CVSS vector is local, low complexity, low privileges, no user interaction. The source bundle marks KEV as false and provides no cited evidence of active exploitation.

Researcher notes

The bundle supports a local kernel Btrfs CWE-416 assessment, but lacks distribution-specific fixed packages, proof-of-concept details, and real-world exploitation evidence. Avoid extrapolating beyond upstream stable commits and CVSS metadata.

Mitigation direction

  • Apply kernel updates containing the referenced upstream stable Btrfs fixes.
  • Check your Linux distribution security advisory for backported kernel packages.
  • Prioritize multi-user systems and hosts using Btrfs filesystems.
  • Limit unnecessary local account access until patched.
  • Monitor vendor advisories for corrected affected-version guidance.

Validation and detection

  • Inventory Linux hosts and identify those using Btrfs.
  • Compare running kernels against vendor fixed versions or referenced stable commits.
  • Confirm whether distribution kernels backported the Btrfs fix.
  • Check vulnerability scanners for CVE-2022-49761 coverage and false positives.
  • Document systems where Btrfs is absent or the kernel is fixed.
Prepared
Confidence
medium
Sources
6

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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-416: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2022-49761 mapping review

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Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

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.

1CVSS vectors
3Timeline events
1ADP providers
5Source links

SSVC decision data

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

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2022-49761Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
cvssV3_1other:ssvc
Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux79787eaab46121d4713ed03c8fc63b9ec3eaec76, 79787eaab46121d4713ed03c8fc63b9ec3eaec76, 79787eaab46121d4713ed03c8fc63b9ec3eaec76, 79787eaab46121d4713ed03c8fc63b9ec3eaec76unaffected
LinuxLinux3.4, 0, 5.10.165, 5.15.90, 6.1.8, 6.2affected
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-416 · source CWE mapping

Use After Free

Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.