CVE-2026-72210 ntfs: fix off-by-one in mapping pairs decoding bounds checks
An off-by-one error in the Linux kernel NTFS driver allows out-of-bounds reads, potentially leading to information disclosure or system crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72210?
CVE-2026-72210 is a critical memory corruption vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-72210?
How do I fix CVE-2026-72210?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-72210 being exploited?
There is no known exploitation of CVE-2026-72210 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-72210, GHSA-hpv2-jq93-768m, UBUNTU-CVE-2026-72210.