CVE-2026-64600: xfs: resample the data fork mapping after cycling ILOCK
In the Linux kernel, the following vulnerability has been resolved:
xfs: resample the data fork mapping after cycling ILOCK
xfsreflinkfill{cowhole,delalloc} are both presented with an inode, a data fork mapping, and a cow fork mapping. Unfortunately, these two helpers cycle the ILOCK to grab a transaction, which means that the mappings are stale as soon as we reacquire the ILOCK. Currently we refresh the cow fork mapping by re-calling xfsfindtrimcowextent, but we don't refresh the data fork mapping beforehand, which means that the xfsbmaptrimcow in that function queries the refcount btree about the wrong physical blocks and returns an inaccurate value in shared.
If shared is now false, the directio write proceeds with a stale data fork mapping. Fix this by querying the data fork mapping if the sequence counter changes across the ILOCK cycle.
Other sources
reflinking a file may lead cause a data corruption
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.145.2-1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64600?
CVE-2026-64600 has a severity rating of high, specifically a score of 7.
What does CVE-2026-64600 affect?
CVE-2026-64600 affects the Linux kernel, specifically the XFS file system.
How do I fix CVE-2026-64600?
To fix CVE-2026-64600, ensure that your Linux kernel is updated to the latest version that contains the security patch.
What kind of vulnerability is CVE-2026-64600?
CVE-2026-64600 is a vulnerability related to improper handling of inode mappings within the Linux kernel's XFS file system.
When was CVE-2026-64600 published?
CVE-2026-64600 was published on July 10, 2026.