CVE-2026-72193

What it is

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).

At a glance

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-08-15 06:21 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-06 17:19 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: not scored yet.
• Fix: none linked yet, which raises it.

Details

Published

2026-08-15 06:21 UTC

Last modified

2026-11-06 17:19 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Received

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