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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72193
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:21:37 UTC
Updated2026-08-15 06:21:37 UTC
DescriptionIn 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).

Risk And Classification

EPSS: 0.002050000 probability, percentile 0.108580000 (date 2026-08-15)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected b46acd6a6a627d876898e1c84d3f84902264b445 8128bec895075253c779d67afdc90ae513265fca git Not specified
CNA Linux Linux affected b46acd6a6a627d876898e1c84d3f84902264b445 7972df425687daa70d971fe6ed415e78683133dd git Not specified
CNA Linux Linux affected b46acd6a6a627d876898e1c84d3f84902264b445 7ac4c86915c24c208a0f0611b71d9676686fe756 git Not specified
CNA Linux Linux affected b46acd6a6a627d876898e1c84d3f84902264b445 29b86dbe88cbbef53bb9aaec2e279359f8c450f8 git Not specified
CNA Linux Linux affected b46acd6a6a627d876898e1c84d3f84902264b445 0fad25687d4d3fa1fdd313d31b9cb5817c425029 git Not specified
CNA Linux Linux affected b46acd6a6a627d876898e1c84d3f84902264b445 d313416280d41bea272f02a6034dfa88008692a0 git Not specified
CNA Linux Linux affected b46acd6a6a627d876898e1c84d3f84902264b445 9611f644302c07d21bc8af97e3e06a3d30064253 git Not specified
CNA Linux Linux affected 5.15 Not specified
CNA Linux Linux unaffected 5.15 semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/d313416280d41bea272f02a6034dfa88008692a0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0fad25687d4d3fa1fdd313d31b9cb5817c425029 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/29b86dbe88cbbef53bb9aaec2e279359f8c450f8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8128bec895075253c779d67afdc90ae513265fca 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9611f644302c07d21bc8af97e3e06a3d30064253 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7972df425687daa70d971fe6ed415e78683133dd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7ac4c86915c24c208a0f0611b71d9676686fe756 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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