{"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:\n\nntfs3: cap RESTART_TABLE free-chain walker at rt->used\n\nA crafted NTFS3 disk image triggers an in-kernel infinite loop at\nmount 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","slug":"CVE-2026-72193","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: cap RESTART_TABLE free-chain walker at rt->used\n\nA crafted NTFS3 disk image triggers an in-kernel infinite loop at\nmount time, hanging the mounting thread and firing the soft-lockup\nwatchdog within ~22s on multi-CPU hosts (panic with\nkernel.softlockup_panic=1).  The bug is reachable from desktop USB\nauto-mount on distributions where udisks2 routes the NTFS signature\nto the in-tree ntfs3 driver (Arch family and an increasing fraction\nof Fedora / openSUSE / RHEL deployments); CAP_SYS_ADMIN-class manual\nmount elsewhere.\n\ncheck_rstbl()'s second walker iterates the free-entry singly-linked\nlist headed by rt->first_free with no upper bound on iteration count:\n\n  for (off = ff; off;) {\n      if (off == RESTART_ENTRY_ALLOCATED)\n          return false;\n      off = le32_to_cpu(*(__le32 *)Add2Ptr(rt, off));\n      if (off > ts - sizeof(__le32))\n          return false;\n  }\n\nThe existing guards cover three exits: end-of-list (off == 0), the\nin-use marker (off == RESTART_ENTRY_ALLOCATED), and out-of-bounds\n(off > ts - sizeof(__le32)).  None of the three prevents an\nin-bounds cycle.\n\nA crafted on-disk RESTART_TABLE whose free chain contains a\nself-loop or A->B->A cycle whose offsets satisfy:\n\n  - in range [sizeof(struct RESTART_TABLE), ts - sizeof(__le32)]\n  - (off - sizeof(struct RESTART_TABLE)) % rsize == 0\n\npasses all existing guards and spins the mount-time thread forever.\nReproduced in UML by hand-forging a 2 MB NTFS3 image whose journal\nRESTART_TABLE first_free = 0x18 and whose entry at offset 0x18\nstores 0x18 as its next pointer; mount of the forged image with\nthe in-tree ntfs3 driver never returns.\n\nBound the walker by rt->used.  Each entry on a legitimate free\nchain is unique, and the total slot count is ne = le16_to_cpu\n(rt->used).  A traversal that visits more than ne slots is by\nconstruction malformed; reject it as a corrupt RESTART_TABLE.\n\nAfter this patch, mount of the forged image returns with -EINVAL\nand a log_replay failure message, and mkntfs-produced legitimate\nimages mount cleanly (verified in the same UML harness).\n\n## Affected\n\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 8128bec895075253c779d67afdc90ae513265fca`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 7972df425687daa70d971fe6ed415e78683133dd`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 7ac4c86915c24c208a0f0611b71d9676686fe756`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 29b86dbe88cbbef53bb9aaec2e279359f8c450f8`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 0fad25687d4d3fa1fdd313d31b9cb5817c425029`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < d313416280d41bea272f02a6034dfa88008692a0`\n- `Linux >= b46acd6a6a627d876898e1c84d3f84902264b445 < 9611f644302c07d21bc8af97e3e06a3d30064253`\n- `Linux 5.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}