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.
- CVSS v3.1
- 7.8 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS
- 0.47% chance of exploitation in the next 30 days, 39th percentile
- Published
- 2026-07-23
- Updated
- 2026-08-17
Proof-of-concept exploits (8)
- 0xBlackash/CVE-2026-6460021★ · 2026-07-23
- litosmartin/CVE-2026-64600-Refluxfs-PoC3★ · 2026-07-30
- HORKimhab/CVE-2026-646000★ · 2026-08-24
- bha-vin/CVE-2026-64600-Exploit0★ · 2026-07-28
- masrikky/CVE-2026-64600-RefluXFS1★ · 2026-08-08
- 0xSec1/CVE-2026-64600-RefluXFS-PoC0★ · 2026-08-14
- Debajyoti0-0/CVE-2026-64600
- letsr00t/RefluxFS_CVE-2026-64600