CVE-2026-64600

HIGHCVSS 7.8/10EPSS 0.49%

Last modified

CVE-2026-64600 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.49% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.49%

39.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5, < dc11be133efca5fe3a2fb02b016dee825cc12f18; >= 3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5, < b8c9aa832b52680ee40d6cab0efb081f9a69df05; >= 3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5, < 50f0012da1040f69a4e788cd9aed587c9a04983f; >= 3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5, < e705d81a7193dd19e69b8e2bad4696d78a4ea075; >= 3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5, < 206c09b04dc5469c7ff14d8aceff2d47c88078d9; >= 3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5, < 44f891bc088958399eec27f7604928694aa35581; >= 3c68d44a2b49a0ac9165faa9c191e1e618c8a8d5, < 2f4acd0fcd862e22eab45690ec2c08c80b6ef2e7
LinuxLinux4.11

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-64600?
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.
How severe is CVE-2026-64600?
CVE-2026-64600 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.49% probability of exploitation in the next 30 days.
How do I fix CVE-2026-64600?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST