CVE-2025-22000

In the Linux kernel, the following vulnerability has been resolved:

mm/huge_memory: drop beyond-EOF folios with the right number of refs

When an after-split folio is large and needs to be dropped due to EOF, folio_put_refs(folio, folio_nr_pages(folio)) should be used to drop all page cache refs. Otherwise, the folio will not be freed, causing memory leak.

This leak would happen on a filesystem with blocksize > page_size and a truncate is performed, where the blocksize makes folios split to >0 order ones, causing truncated folios not being freed.

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/14efb4793519d73fb2902bb0ece319b886e4b4b9
• https://git.kernel.org/stable/c/86368616a9ce51f6b41efa251b6e066893851d67
• https://git.kernel.org/stable/c/92ad820a1f2d95d5a8d6c2bd3f391bbb068a5f9e