CVE-2026-64600
xfs: resample the data fork mapping after cycling ILOCK
Description
In the Linux kernel, the following vulnerability has been resolved: xfs: resample the data fork mapping after cycling ILOCK xfs_reflink_fill_{cow_hole,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 xfs_find_trim_cow_extent, but we don't refresh the data fork mapping beforehand, which means that the xfs_bmap_trim_cow 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.
INFO
Published Date :
July 23, 2026, 6:16 a.m.
Last Modified :
July 23, 2026, 8:16 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-64600
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update the Linux kernel to the latest stable version.
- Verify that the xfs_reflink_fill helpers are updated.
- Ensure data fork mapping is refreshed after ILOCK cycle.
- Query data fork mapping if sequence counter changes.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64600.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64600 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64600
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64600 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64600 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Jul. 23, 2026
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2026/07/22/14 Added Reference http://www.openwall.com/lists/oss-security/2026/07/22/18 Added Reference http://www.openwall.com/lists/oss-security/2026/07/22/19 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 23, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5', 'lessThan': 'e705d81a7193dd19e69b8e2bad4696d78a4ea075', 'versionType': 'git'}, {'status': 'affected', 'version': '3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5', 'lessThan': '206c09b04dc5469c7ff14d8aceff2d47c88078d9', 'versionType': 'git'}, {'status': 'affected', 'version': '3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5', 'lessThan': '44f891bc088958399eec27f7604928694aa35581', 'versionType': 'git'}, {'status': 'affected', 'version': '3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5', 'lessThan': '2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7', 'versionType': 'git'}], 'programFiles': ['fs/xfs/xfs_reflink.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.11'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.11', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc4', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/xfs/xfs_reflink.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: xfs: resample the data fork mapping after cycling ILOCK xfs_reflink_fill_{cow_hole,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 xfs_find_trim_cow_extent, but we don't refresh the data fork mapping beforehand, which means that the xfs_bmap_trim_cow 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. Added Reference https://git.kernel.org/stable/c/206c09b04dc5469c7ff14d8aceff2d47c88078d9 Added Reference https://git.kernel.org/stable/c/2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7 Added Reference https://git.kernel.org/stable/c/44f891bc088958399eec27f7604928694aa35581 Added Reference https://git.kernel.org/stable/c/e705d81a7193dd19e69b8e2bad4696d78a4ea075