CVE-2026-64600
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 0.51% 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
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Linux | Linux Kernel | >= 4.11, < 5.15.212 | — |
| Linux | Linux Kernel | >= 5.16, < 6.1.178 | — |
| Linux | Linux Kernel | >= 6.2, < 6.6.145 | — |
| Linux | Linux Kernel | >= 6.7, < 6.12.96 | — |
| Linux | Linux Kernel | >= 6.13, < 6.18.39 | — |
| Linux | Linux Kernel | >= 6.19, < 7.1.4 | — |
| Linux | Linux Kernel | 7.2 | Rc1 |
References
- https://cdn2.qualys.com/advisory/2026/07/22/RefluXFS.txtExploit, Third Party Advisory
- https://www.openwall.com/lists/oss-security/2026/07/22/14Mailing List, Exploit
Timeline
- Published
- Last Modified
- Status
- Analyzed
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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