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CVE Record

CVE-2024-49902: jfs: check if leafidx greater than num leaves per dmap tree

In the Linux kernel, the following vulnerability has been resolved: jfs: check if leafidx greater than num leaves per dmap tree syzbot report a out of bounds in dbSplit, it because dmt_leafidx greater than num leaves per dmap tree, add a checking for dmt_leafidx in dbFindLeaf. Shaggy: Modified sanity check to apply to control pages as well as leaf pages.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in the Linux JFS filesystem can cause kernel memory access outside expected bounds. An authenticated local user may be able to trigger serious confidentiality, integrity, or availability impact on systems using a vulnerable kernel. The supplied evidence does not establish real-world exploitation.

Executive priority

Treat as a high-priority kernel maintenance issue for systems using JFS, especially multi-user or otherwise locally accessible hosts. It is not presently an emergency driven by known exploitation. Inventory exposure promptly, apply supported kernel updates during the next accelerated maintenance window, and escalate any internet-facing appliance whose vendor confirms exposure.

Technical view

The JFS dbFindLeaf path did not adequately validate dmt_leafidx before dbSplit used it, allowing an out-of-bounds condition when the index exceeded the dmap tree's leaf count. The correction adds a sanity check covering control and leaf pages. CVSS 3.1 is 7.8: local access, low complexity, low privileges, no user interaction, and potentially high impact.

Likely exposure

Exposure is limited to Linux systems running an affected kernel where JFS functionality is present and reachable. Systems actively using JFS deserve priority. The supplied version data is not sufficiently structured to determine every vulnerable distribution kernel reliably; confirm status against the distribution or appliance vendor's advisory and package changelog.

Exploitation context

The CVSS vector describes a local, low-privilege attack requiring no user interaction. The issue was reported by syzbot, but the bundle provides no exploit details or evidence of attacks in the wild. It is not listed in CISA KEV. Exact triggering prerequisites and practical exploitability are not established by the supplied sources.

Researcher notes

The root condition is an unchecked dmt_leafidx exceeding the number of leaves in a dmap tree. The revised sanity check covers both control and leaf pages. Although CVSS assigns high impact across confidentiality, integrity, and availability, the supplied record does not explain whether practical outcomes are limited to crashes or can reliably achieve broader compromise.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable upstream stable fix.
  • Follow distribution or appliance vendor guidance for backported package versions.
  • Prioritize systems using JFS or permitting untrusted local users.
  • Restrict local access until affected systems are updated.

Validation and detection

  • Record each system's running kernel and distribution package version.
  • Determine whether JFS is configured, loaded, or used by mounted filesystems.
  • Match package changelogs against CVE-2024-49902 or the referenced stable commits.
  • Reboot after updating and verify the fixed kernel is running.
  • Monitor vendor advisories for revised affected-version or exploitation information.
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

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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CVE-2024-49902 mapping review

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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
3ADP providers
14Source links

SSVC decision data

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

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:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2024-49902Attack 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
other:ssvc
CVECVE Program Container
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2unaffected
LinuxLinux2.6.12, 0, 4.19.323, 5.4.285, 5.10.227, 5.15.168, 6.1.113, 6.6.55, 6.10.14, 6.11.3, 6.12affected
Weakness

CWE details

No CWE listed

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