CVE-2026-98139: ntfs: only count successfully cleared runs when freeing clusters

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-25 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: ntfs: only count successfully cleared runs when freeing clusters ntfs_cluster_free_from_rl_nolock() adds a run's length to nr_freed whenever the error bookkeeping condition is false, which includes cases where ntfs_bitmap_clear_run() actually failed - e.g. a second run failing with the same errno as an earlier one, or any failure after a non-ENOMEM error was already recorded. Since a failed ntfs_bitmap_clear_run() rolls back its partial modifications, no bits were cleared for that run, yet its length still inflates vol->free_clusters, corrupting statfs output and the allocator's free space gate. Only count runs whose bitmap clear succeeded.

Affected products

Linux kernel: from 7.1 before 7.2.7; 7.3-rc1 — fixed in 7.2.7

How to fix

Upgrade to a fixed version: Linux kernel 7.2.7. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-98139 or the next vulnerability affects your stack