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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-90199

fs/ntfs3: reject out-of-range evcn in mi_enum_attr()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: reject out-of-range evcn in mi_enum_attr() In mi_enum_attr(), the start/end VCN validation for non-resident attributes is: if (svcn > evcn + 1) goto out; When evcn is U64_MAX the "evcn + 1" expression wraps to 0 and any svcn passes the check. For evcn values close to U64_MAX (but not equal to it) the right-hand side is still a meaningless near-wrap upper bound, so a malformed on-disk attribute with svcn == 0 and evcn near U64_MAX can pass mi_enum_attr() unrejected. VCN (virtual cluster number) is a cluster index, so any valid evcn is bounded by the volume's total cluster count, which ntfs3 holds in sbi->used.bitmap.nbits (set up in ntfs_init_from_boot() before any caller of mi_enum_attr() runs). Reject evcn values that fall outside this range. However, an empty non-resident attribute (no allocated clusters) is legitimately encoded with svcn == 0 and evcn == -1 (U64_MAX), e.g. via attr->nres.evcn = cpu_to_le64((u64)vcn - 1) with vcn == 0. That sentinel must keep passing, so exclude evcn == U64_MAX from the range check. The existing "svcn > evcn + 1" test still tolerates the sentinel ("0 > 0" is false) and continues to require svcn == 0 for it, while the range check rejects every other out-of-range evcn and thereby also defuses the "evcn + 1" wraparound. svcn does not need its own bound: once evcn < nbits, "svcn > evcn + 1" implies svcn <= nbits. [almaz.alexandrovich@paragon-software.com: fixed evcn check]

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

  • 013ff63b649475f0ee134e2c8d0c8e65284ede50 to < 0441e34ce098c19185a7b52c5b8b89a8a5b26888affected
  • 013ff63b649475f0ee134e2c8d0c8e65284ede50 to < 7ab69cef49ebdfee288287d62641b24ab1445eccaffected
  • 013ff63b649475f0ee134e2c8d0c8e65284ede50 to < ce9a619c432b9a4044fee115c5483fbed946c131affected
  • 013ff63b649475f0ee134e2c8d0c8e65284ede50 to < 2b9a0e57bfd365e2096706b19ae34dce3b4a884baffected
  • 013ff63b649475f0ee134e2c8d0c8e65284ede50 to < 20fd9f64c0050658f2031e6bd5d552c6f0c8f7e3affected
  • a7accf181a4709a6e380360372150cc4a1b6b89aaffected
  • 3dfd727873c3e8da74a2e3907120ff052c5f0bccaffected
  • 1d7dd485108d4f633b543c9c14071cc325b68ae5affected
  • 5.15.209 to < 5.16affected
  • 6.1.115 to < 6.2affected
  • 6.5.11 to < 6.6affected

Linux Linux

Default version status: affected

  • 6.6affected
  • 0 to < 6.6unaffected
  • 6.6.157 to ≤ 6.6.*unaffected
  • 6.12.110 to ≤ 6.12.*unaffected
  • 6.18.52 to ≤ 6.18.*unaffected
  • 7.2.6 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References