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CVE PROGRAM SOURCE RECORD8.4 High

CVE-2026-72196

fs/ntfs3: bound copy_lcns dp->page_lcns[] index in analysis pass

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: bound copy_lcns dp->page_lcns[] index in analysis pass In log_replay()'s analysis pass, after find_dp() returns a valid DIR_PAGE_ENTRY for the (target_attr, target_vcn) tuple, the copy_lcns block walks lrh->lcns_follow further entries: t16 = le16_to_cpu(lrh->lcns_follow); for (i = 0; i < t16; i++) { size_t j = (size_t)(le64_to_cpu(lrh->target_vcn) - le64_to_cpu(dp->vcn)); dp->page_lcns[j + i] = lrh->page_lcns[i]; } find_dp() only validates that target_vcn falls within [dp->vcn, dp->vcn + dp->lcns_follow), i.e., that the FIRST cluster is covered. The walk through the further entries is not bounded against dp->lcns_follow. For a malformed LRH where target_vcn = dp->vcn + dp->lcns_follow - 1 and lrh->lcns_follow > 1, the i > 0 writes overflow the dp's allocated page_lcns[] array. Add the missing j + lrh->lcns_follow <= dp->lcns_follow guard. Reproduced under UML+KASAN on mainline 8d90b09e6741 as a slab-out-of-bounds write of size 8 from log_replay+0x68d4 on the mount path. This is distinct from Pavitra Jha's 2026-05-02 patch ("fs/ntfs3: validate lcns_follow in log_replay conversion", <20260502154252.164586-1-jhapavitra98@gmail.com>) which addresses the separate version-0 dirty-page-table conversion path's memmove(&dp->vcn, ...) call. The two fixes are complementary; both should land. [almaz.alexandrovich@paragon-software.com: clang-formatted the changes, fixed conflicts]

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • b46acd6a6a627d876898e1c84d3f84902264b445 to < 9b3d8cc9d54fcded4de51b2b1026ae7182512077affected
  • b46acd6a6a627d876898e1c84d3f84902264b445 to < 9b7c28d8c61bdb041936222a09a708531a1c2921affected
  • b46acd6a6a627d876898e1c84d3f84902264b445 to < 0f13e823bf86bd1800168ea0bb5bca8b8500a81caffected
  • b46acd6a6a627d876898e1c84d3f84902264b445 to < d240cd98f5f7b65c90f6b2b6abe3232ccdc405abaffected
  • b46acd6a6a627d876898e1c84d3f84902264b445 to < 49c86dae0c0ccb8d98ddcdc46987259389c816ddaffected
  • b46acd6a6a627d876898e1c84d3f84902264b445 to < 5e7b598660cfa8e5af172cf4c65cffc126333307affected

Linux Linux

Default version status: affected

  • 5.15affected
  • 0 to < 5.15unaffected
  • 6.1.178 to ≤ 6.1.*unaffected
  • 6.6.145 to ≤ 6.6.*unaffected
  • 6.12.97 to ≤ 6.12.*unaffected
  • 6.18.40 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References