Description
In the Linux kernel, the following vulnerability has been resolved:

ntfs: fix u16 truncation of restart-area length check

ntfs_check_restart_area() validates that the $LogFile restart area and
its trailing log client record array fit within the system page size:

u16 ra_ofs, ra_len, ca_ofs;
...
ra_len = ca_ofs + le16_to_cpu(ra->log_clients) *
sizeof(struct log_client_record);
if (ra_ofs + ra_len > le32_to_cpu(rp->system_page_size) || ...)
return false;

ra_len is u16, but the right-hand side is computed in size_t
(sizeof(struct log_client_record) == 160). Both ca_ofs and log_clients
come straight from the on-disk restart area. With an on-disk
log_clients of 410 the product 410 * 160 = 65600; adding ca_ofs and
storing into the u16 ra_len truncates modulo 65536 (e.g. ca_ofs 64
gives ra_len 128), so the "fits in the page" check passes even though
the client array described by log_clients extends far beyond the page.

ntfs_check_log_client_array() then walks the array bounded only by the
on-disk log_clients count:

cr = ca + idx;
if (cr->prev_client != LOGFILE_NO_CLIENT) ...

For log_clients 410 it dereferences records up to ca + 409 * 160,
~64 KiB past the kvzalloc(system_page_size) restart-page buffer -- an
out-of-bounds read of attacker-controlled extent, reachable when a
crafted NTFS image is mounted (load_and_check_logfile() at mount time).
This is the in-kernel analogue of CVE-2022-30789, fixed in the ntfs-3g
userspace driver but never in this revived classic driver.

Compute the restart-area length in a u32 so the existing bounds check
rejects an over-large client array instead of being defeated by the
truncation. Widen ra_ofs and ca_ofs to u32 as well: both are loaded
from __le16 on-disk fields and every comparison already promotes to
int/size_t, so this changes no result and keeps the declaration uniform.
Published: 2026-08-28
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

An incorrect size verification in the kernel NTFS driver causes a 16‑bit counter to wrap when an NTFS volume contains a large client array. The resulting truncation allows the driver to believe the buffer fits in a page while in fact the array extends far beyond the allocation. When the volume is mounted, the driver walks the malformed array and performs an out‑of‑bounds read from memory that the attacker can control. The read may leak sensitive data or provoke a kernel fault.

Affected Systems

All Linux kernel versions that include the classic NTFS driver without the fix from commit 07a4751ef3.. The patch addresses the issue in the latest kernel releases; versions prior to that commit are vulnerable.

Risk and Exploitability

The CVSS score is not listed, and the EPSS is not available, but the vulnerability is present in kernel code that executes during filesystem mount, giving an attacker local or privileged access to craft a malicious NTFS image. Because the exploit requires mounting a malicious file system, it is not remotely triggerable via network traffic. The risk is moderate; the kernel may crash or expose memory contents. The vulnerability is not yet catalogued in CISA's KEV.

Generated by OpenCVE AI on August 28, 2026 at 09:54 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the kernel patch referenced in the advisory (commits 07a4751ef3... and 390936fb15...), which widens the affected variables to 32‑bits to prevent truncation.
  • If a patch cannot be applied immediately, avoid mounting untrusted NTFS volumes or use a read‑only mount to limit the impact of any out‑of‑bounds read.
  • Upgrade the system to a recent kernel that includes the fix to eliminate the vulnerability altogether.

Generated by OpenCVE AI on August 28, 2026 at 09:54 UTC.

Tracking

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Advisories

No advisories yet.

History

Fri, 28 Aug 2026 10:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-787

Fri, 28 Aug 2026 07:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ntfs: fix u16 truncation of restart-area length check ntfs_check_restart_area() validates that the $LogFile restart area and its trailing log client record array fit within the system page size: u16 ra_ofs, ra_len, ca_ofs; ... ra_len = ca_ofs + le16_to_cpu(ra->log_clients) * sizeof(struct log_client_record); if (ra_ofs + ra_len > le32_to_cpu(rp->system_page_size) || ...) return false; ra_len is u16, but the right-hand side is computed in size_t (sizeof(struct log_client_record) == 160). Both ca_ofs and log_clients come straight from the on-disk restart area. With an on-disk log_clients of 410 the product 410 * 160 = 65600; adding ca_ofs and storing into the u16 ra_len truncates modulo 65536 (e.g. ca_ofs 64 gives ra_len 128), so the "fits in the page" check passes even though the client array described by log_clients extends far beyond the page. ntfs_check_log_client_array() then walks the array bounded only by the on-disk log_clients count: cr = ca + idx; if (cr->prev_client != LOGFILE_NO_CLIENT) ... For log_clients 410 it dereferences records up to ca + 409 * 160, ~64 KiB past the kvzalloc(system_page_size) restart-page buffer -- an out-of-bounds read of attacker-controlled extent, reachable when a crafted NTFS image is mounted (load_and_check_logfile() at mount time). This is the in-kernel analogue of CVE-2022-30789, fixed in the ntfs-3g userspace driver but never in this revived classic driver. Compute the restart-area length in a u32 so the existing bounds check rejects an over-large client array instead of being defeated by the truncation. Widen ra_ofs and ca_ofs to u32 as well: both are loaded from __le16 on-disk fields and every comparison already promotes to int/size_t, so this changes no result and keeps the declaration uniform.
Title ntfs: fix u16 truncation of restart-area length check
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-28T06:49:12.340Z

Reserved: 2026-08-26T14:34:25.782Z

Link: CVE-2026-80672

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-28T08:16:52.510

Modified: 2026-08-28T08:16:52.510

Link: CVE-2026-80672

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-28T10:00:06Z

Weaknesses