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CVE-2026-45864 Linux CVE debrief

A vulnerability in the Linux kernel's NTFS3 filesystem driver could allow an attacker to trigger an infinite loop, leading to a denial of service (system hang). The issue occurs when processing valid values within a specific range; if the retrieved valid value remains unchanged, the loop never terminates. This was reported by syzbot, which observed a task blocked for over 143 seconds. The fix adds a check within the loop to detect when the valid value does not progress and returns -EINVAL to prevent the hang. The vulnerability affects the ntfs_file_write_iter function in fs/ntfs3/file.c.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-27
Original CVE updated
2026-06-25
Advisory published
2026-05-27
Advisory updated
2026-06-25

Who should care

System administrators running Linux systems with NTFS3 filesystem support enabled; security teams monitoring for denial-of-service conditions; organizations using NTFS-formatted storage on Linux infrastructure

Technical summary

The NTFS3 filesystem driver in the Linux kernel contains a logic error in fs/ntfs3/file.c where the ntfs_file_write_iter function can enter an infinite loop. When iterating through valid values in the range [valid : pos), if the next valid value retrieved is identical to the current value, the loop condition never progresses toward termination. The vulnerability was discovered through syzbot fuzzing, which triggered a 143+ second task block. The fix introduces a check within the loop body to detect stagnant valid values and returns -EINVAL to force loop termination. Seven stable kernel commits are referenced, indicating backports to multiple supported kernel versions.

Defensive priority

high

Recommended defensive actions

  • Apply kernel updates containing the referenced stable tree commits when available from your Linux distribution
  • Monitor vendor security advisories for patched kernel packages
  • If NTFS3 filesystem support is not required, consider disabling the ntfs3 module as a temporary mitigation
  • Review systems for unexpected hangs or high CPU usage in ntfs3-related operations

Evidence notes

The CVE description confirms the vulnerability is in fs/ntfs3 and involves an infinite loop when processing valid values. The syzbot report shows a task blocked for 143+ seconds with a call trace through ntfs_file_write_iter. Seven kernel.org stable tree commits are provided as references, indicating fixes across multiple kernel versions.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-45864 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-45864

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-45864 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-45864

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/27b75ca4e51e3e4554dc85dbf1a0246c66106fd3

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/4bf3bafb8e0635ed93e3cd4156dcbcc0fb960cb4

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/50c822fcb36768f1fb356f05b02a2248ef81936d

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/6d93239b4fc479f7c0a412dd196ec0ca2672d14a

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/71c8b966ec56e13c02388c1312910588bb49be7a

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/a47a2bb9aa6455d5cee1045814a60c749309c92b

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/b97e371e5d1c13d722335d46eb8bc1a22b272a0e

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.