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.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No vendor fix or workaround currently provided.
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Sat, 15 Aug 2026 06:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | ntfs: fix off-by-one in mapping pairs decoding bounds checks | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T05:54:05.527Z
Reserved: 2026-08-09T03:40:39.912Z
Link: CVE-2026-72210
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-08-15T06:21:39.713
Modified: 2026-08-15T06:21:39.713
Link: CVE-2026-72210
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.