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☀ Commemorated today: The Miracle of the Universal Key (2021)Saint RefluXFS, Who Refluxed Into the Files You Read
Patron of the XFS filesystem, copy-on-write, and locks released a moment too long.
Life
In July 2026 Saeed Abbasi of Qualys revealed RefluXFS (CVE-2026-64600), a race condition in the XFS reflink path. By releasing and reacquiring the lock, the file mappings went stale, and a local user could thus overwrite the on-disk contents of any readable file, /etc/passwd included, to become root. The flaw had been in the kernel since 2017 and hit many distributions with an XFS root by default.
Prayer
O Saint RefluXFS, who refluxes your data into other people's files, teach our filesystems to re-read the mappings after every pause. Amen.
How to celebrate
Celebrated by updating the kernel with the 16 July 2026 patch and checking whether your root really is XFS with reflink.
Release the lock an instant, and the map has already changed.