Bug 2516486 (CVE-2026-72210) - CVE-2026-72210 kernel: ntfs: fix off-by-one in mapping pairs decoding bounds checks
Summary: CVE-2026-72210 kernel: ntfs: fix off-by-one in mapping pairs decoding bounds ...
Keywords:
Status: NEW
Alias: CVE-2026-72210
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-15 06:15 UTC by OSIDB Bzimport
Modified: 2026-08-18 15:46 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-08-15 06:15:04 UTC
In the Linux kernel, the following vulnerability has been resolved:

ntfs: fix off-by-one in mapping pairs decoding bounds checks

In ntfs_mapping_pairs_decompress(), attr_end points one byte past the
end of the attribute record:

    attr_end = (u8 *)attr + le32_to_cpu(attr->length);

The two bounds checks validating that mapping pair data bytes fit within
the attribute use strict greater-than (>), which allows a one-byte
out-of-bounds read when the data extends exactly to attr_end:

  b = *buf & 0xf;
  if (b) {
      if (unlikely(buf + b > attr_end))   // off-by-one
          goto io_error;
      for (deltaxcn = (s8)buf[b--]; b; b--)
          deltaxcn = (deltaxcn << 8) + buf[b];
  }

When buf + b == attr_end, the check evaluates to false and buf[b] reads
one byte past the valid attribute boundary. The same pattern appears in
the LCN delta bytes check.

Fix both checks to use >= so that buf[b] at exactly attr_end is
correctly rejected as out of bounds.


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