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CVE Record

CVE-2026-45935: fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot In the 'DeleteIndexEntryRoot' case of the 'do_action' function, the entry size ('esize') is retrieved from the log record without adequate bounds checking. Specifically, the code calculates the end of the entry ('e2') using: e2 = Add2Ptr(e1, esize); It then calculates the size for memmove using 'PtrOffset(e2, ...)', which subtracts the end pointer from the buffer limit. If 'esize' is maliciously large, 'e2' exceeds the used buffer size. This results in a negative offset which, when cast to size_t for memmove, interprets as a massive unsigned integer, leading to a heap buffer overflow. This commit adds a check to ensure that the entry size ('esize') strictly fits within the remaining used space of the index header before performing memory operations.

HighCVSS 7.8Not KEV-listedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in Linux’s NTFS3 filesystem driver can corrupt kernel memory when it processes a maliciously sized NTFS log entry. Exploitation requires local access and user interaction according to the supplied CVSS data. Successful triggering could crash the system or potentially compromise confidentiality and integrity, although the sources do not demonstrate a specific exploitation outcome.

Executive priority

Treat as a high-priority kernel update for endpoints, forensic systems, virtualization hosts, and other machines that may process untrusted NTFS content. Broader urgency is lower where NTFS3 is unavailable or strictly isolated, but exposure should be verified rather than assumed.

Technical view

DeleteIndexEntryRoot trusted an entry size from an NTFS log record. An oversized value could move a pointer beyond the used index buffer; the resulting negative offset became a massive unsigned memmove length, causing out-of-bounds kernel heap access. The stable commits add a remaining-space bounds check before memory operations.

Likely exposure

Exposure is most likely where affected Linux kernels use NTFS3 to process attacker-controlled or corrupted NTFS volumes. The bundle identifies affected release points from 5.15 through 7.0, but exact distribution and backport status require vendor verification. No direct network attack path is identified.

Exploitation context

The supplied CVSS is 7.8 with local access, low complexity, no privileges, and user interaction required. The CVE is not marked as KEV, and the cited sources provide no evidence of active exploitation or a public exploit. Absence from KEV does not prove exploitation has never occurred.

Researcher notes

The title describes a slab out-of-bounds read, while the detailed description characterizes the unsafe memmove as a heap buffer overflow. The sources establish faulty bounds handling and memory corruption risk, but do not establish reliable code execution. The simplified affected-version list is insufficient for precise distribution package conclusions.

Mitigation direction

  • Install a vendor kernel containing the applicable referenced stable fix or confirmed backport.
  • Consult the Linux distribution’s security advisory for exact package and reboot requirements.
  • Until patched, restrict processing of untrusted or removable NTFS volumes where operationally feasible.
  • Prioritize systems where untrusted users can supply NTFS media or disk images.

Validation and detection

  • Inventory running kernel versions and determine whether NTFS3 is enabled or used.
  • Compare each distribution kernel build with its vendor advisory and backport status.
  • Confirm the installed kernel contains the applicable stable fix, then reboot into it.
  • Review NTFS mount workflows for attacker-controlled physical media, images, or volumes.
Prepared
Confidence
medium
Sources
9

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-2026-45935 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
8Source 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-2026-45935Attack 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.

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxb46acd6a6a627d876898e1c84d3f84902264b445, b46acd6a6a627d876898e1c84d3f84902264b445, b46acd6a6a627d876898e1c84d3f84902264b445, b46acd6a6a627d876898e1c84d3f84902264b445, b46acd6a6a627d876898e1c84d3f84902264b445, b46acd6a6a627d876898e1c84d3f84902264b445, b46acd6a6a627d876898e1c84d3f84902264b445unaffected
LinuxLinux5.15, 0, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0affected
Weakness

CWE details

No CWE listed

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