---
id: CVE-2026-72193
title: 'ntfs3: cap RESTART_TABLE free-chain walker at rt->used'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ntfs3: cap RESTART_TABLE free-chain walker at rt->used

  A crafted NTFS3 disk image triggers an in-kernel infinite loop at
  mount time, hanging the mounting thread and fi…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    8128bec895075253c779d67afdc90ae513265fca
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    7972df425687daa70d971fe6ed415e78683133dd
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    7ac4c86915c24c208a0f0611b71d9676686fe756
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    29b86dbe88cbbef53bb9aaec2e279359f8c450f8
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    0fad25687d4d3fa1fdd313d31b9cb5817c425029
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    d313416280d41bea272f02a6034dfa88008692a0
  - >-
    Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 <
    9611f644302c07d21bc8af97e3e06a3d30064253
  - Linux 5.15
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:52:39.538520Z'
published: '2026-08-15'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:55:22.159Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72193'
references:
  - url: 'https://git.kernel.org/stable/c/8128bec895075253c779d67afdc90ae513265fca'
  - url: 'https://git.kernel.org/stable/c/7972df425687daa70d971fe6ed415e78683133dd'
  - url: 'https://git.kernel.org/stable/c/7ac4c86915c24c208a0f0611b71d9676686fe756'
  - url: 'https://git.kernel.org/stable/c/29b86dbe88cbbef53bb9aaec2e279359f8c450f8'
  - url: 'https://git.kernel.org/stable/c/0fad25687d4d3fa1fdd313d31b9cb5817c425029'
  - url: 'https://git.kernel.org/stable/c/d313416280d41bea272f02a6034dfa88008692a0'
  - url: 'https://git.kernel.org/stable/c/9611f644302c07d21bc8af97e3e06a3d30064253'
tags:
  - cve.org
epss: 0.00215
epssPercentile: 0.11894
ingestedAt: '2026-11-06T18:00:12.589Z'
---

## Overview

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

ntfs3: cap RESTART_TABLE free-chain walker at rt->used

A crafted NTFS3 disk image triggers an in-kernel infinite loop at
mount time, hanging the mounting thread and firing the soft-lockup
watchdog within ~22s on multi-CPU hosts (panic with
kernel.softlockup_panic=1).  The bug is reachable from desktop USB
auto-mount on distributions where udisks2 routes the NTFS signature
to the in-tree ntfs3 driver (Arch family and an increasing fraction
of Fedora / openSUSE / RHEL deployments); CAP_SYS_ADMIN-class manual
mount elsewhere.

check_rstbl()'s second walker iterates the free-entry singly-linked
list headed by rt->first_free with no upper bound on iteration count:

  for (off = ff; off;) {
      if (off == RESTART_ENTRY_ALLOCATED)
          return false;
      off = le32_to_cpu(*(__le32 *)Add2Ptr(rt, off));
      if (off > ts - sizeof(__le32))
          return false;
  }

The existing guards cover three exits: end-of-list (off == 0), the
in-use marker (off == RESTART_ENTRY_ALLOCATED), and out-of-bounds
(off > ts - sizeof(__le32)).  None of the three prevents an
in-bounds cycle.

A crafted on-disk RESTART_TABLE whose free chain contains a
self-loop or A->B->A cycle whose offsets satisfy:

  - in range [sizeof(struct RESTART_TABLE), ts - sizeof(__le32)]
  - (off - sizeof(struct RESTART_TABLE)) % rsize == 0

passes all existing guards and spins the mount-time thread forever.
Reproduced in UML by hand-forging a 2 MB NTFS3 image whose journal
RESTART_TABLE first_free = 0x18 and whose entry at offset 0x18
stores 0x18 as its next pointer; mount of the forged image with
the in-tree ntfs3 driver never returns.

Bound the walker by rt->used.  Each entry on a legitimate free
chain is unique, and the total slot count is ne = le16_to_cpu
(rt->used).  A traversal that visits more than ne slots is by
construction malformed; reject it as a corrupt RESTART_TABLE.

After this patch, mount of the forged image returns with -EINVAL
and a log_replay failure message, and mkntfs-produced legitimate
images mount cleanly (verified in the same UML harness).

## Affected

- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 8128bec895075253c779d67afdc90ae513265fca`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 7972df425687daa70d971fe6ed415e78683133dd`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 7ac4c86915c24c208a0f0611b71d9676686fe756`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 29b86dbe88cbbef53bb9aaec2e279359f8c450f8`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 0fad25687d4d3fa1fdd313d31b9cb5817c425029`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < d313416280d41bea272f02a6034dfa88008692a0`
- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 9611f644302c07d21bc8af97e3e06a3d30064253`
- `Linux 5.15`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.