Bug 2418801 (CVE-2025-40216)

Summary: CVE-2025-40216 kernel: io_uring/rsrc: don't rely on user vaddr alignment
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-12-04 15:02:11 UTC 
In the Linux kernel, the following vulnerability has been resolved:

io_uring/rsrc: don't rely on user vaddr alignment

There is no guaranteed alignment for user pointers, however the
calculation of an offset of the first page into a folio after coalescing
uses some weird bit mask logic, get rid of it.
Comment 1 Alexander B 2025-12-05 17:23:17 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025120417-CVE-2025-40216-d79f@gregkh/T