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CVE Record

CVE-2025-40067: fs/ntfs3: reject index allocation if $BITMAP is empty but blocks exist

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: reject index allocation if $BITMAP is empty but blocks exist Index allocation requires at least one bit in the $BITMAP attribute to track usage of index entries. If the bitmap is empty while index blocks are already present, this reflects on-disk corruption. syzbot triggered this condition using a malformed NTFS image. During a rename() operation involving a long filename (which spans multiple index entries), the empty bitmap allowed the name to be added without valid tracking. Subsequent deletion of the original entry failed with -ENOENT, due to unexpected index state. Reject such cases by verifying that the bitmap is not empty when index blocks exist.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A malformed NTFS filesystem can confuse Linux’s ntfs3 driver during a long-filename rename. The driver may create inconsistent index tracking, causing later deletion to fail. The supplied CVSS score is 7.8, but practical exposure requires local interaction with a crafted or corrupted NTFS filesystem.

Executive priority

Treat this as high priority for endpoints, forensic systems, file-processing services, and infrastructure exposed to untrusted NTFS media or images. Prioritize targeted patching and exposure reduction; the supplied evidence does not justify declaring an active exploitation emergency.

Technical view

When NTFS index blocks exist but the $BITMAP attribute is empty, ntfs3 previously continued despite invalid on-disk state. A long-filename rename could add entries without valid allocation tracking, after which deletion returned -ENOENT. The fix rejects index allocation when this inconsistent condition is detected.

Likely exposure

Exposure is concentrated on systems running versions identified as affected that mount or process malformed NTFS filesystems. Removable media, disk images, recovery workflows, and shared storage handling untrusted NTFS content deserve particular review. The supplied version data is unusual, so distribution-specific advisories should determine actual package exposure.

Exploitation context

The CVSS vector describes local access, low complexity, no privileges, and required user interaction. The source reports syzbot reproduction with a malformed NTFS image. KEV is false, and the supplied sources provide no evidence of active exploitation or a public weaponized exploit.

Researcher notes

The demonstrated failure is index-state inconsistency: an empty $BITMAP coexists with index blocks, a long-name rename proceeds, and original-entry deletion fails with -ENOENT. The source does not establish a precise path from this behavior to the confidentiality, integrity, and availability impacts reflected in CVSS. Affected-version interpretation requires vendor confirmation.

Mitigation direction

  • Update to a vendor-supported kernel containing the referenced ntfs3 validation fix.
  • Check distribution advisories because package versions may not map directly to upstream versions.
  • Restrict mounting or processing untrusted NTFS media and images until remediation is confirmed.
  • Follow vendor guidance for affected kernels not clearly covered by the supplied version data.

Validation and detection

  • Record running kernel and distribution package versions across systems using NTFS.
  • Confirm vendor packages include one of the referenced upstream fixes or an equivalent backport.
  • Identify systems that mount removable, uploaded, shared, or otherwise untrusted NTFS filesystems.
  • Verify in an isolated test that inconsistent index allocation is rejected safely.
  • Monitor kernel and filesystem logs for ntfs3 errors during rename or deletion operations.
Prepared
Confidence
medium
Sources
6

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-2025-40067 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:N/UI:R/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
0ADP providers
5Source links

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:N/UI:R/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-2025-40067Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxb35a50d639ca5259466ef5fea85529bb4fb17d5b, 3ed2cc6a6e93fbeb8c0cafce1e7fb1f64a331dcc, d99208b91933fd2a58ed9ed321af07dacd06ddc3, d99208b91933fd2a58ed9ed321af07dacd06ddc3, 358d4f821c03add421a4c49290538a705852ccf1, a285395020780adac1ffbc844069c3d700bf007a, 6.6.102, 6.12.42, 6.15.10, 6.16.1unaffected
LinuxLinux6.17, 0, 6.6.112, 6.12.53, 6.17.3, 6.18affected
Weakness

CWE details

No CWE listed

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