CVE-2026-89617

Summary

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

fs/ntfs3: validate dirty page table on log replay

Each DIR_PAGE_ENTRY ends in a page_lcns[] array whose length is the on-disk lcns_follow field. check_rstbl() validates the table bookkeeping but never checks that this array fits in the entry, so a crafted lcns_follow lets the v0->v1 conversion memmove and later replay passes run off the entry.

Add check_dp_table() to reject, right after check_rstbl(), any entry larger than its size claims via struct_size() (the same expression used to allocate these entries, so the check is overflow-safe by construction). All consumers can then trust lcns_follow as the real capacity. This covers every page_lcns[] access whose index is bounded by the entry itself (the conversion memmove, the HotFix store via find_dp(), and the self-bounded scan loops). Accesses whose index comes from the log record need a separate bound and are handled in a follow-up patch.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/1200c2779c43b62656ccbb67df9468a7a9af2484
• https://git.kernel.org/stable/c/2d94ffc9d7b5bb3517b129fe63b52d84bcd4ae56
• https://git.kernel.org/stable/c/0908da07c23be4f94b99dfd9a94765525f0fe4bd
• https://git.kernel.org/stable/c/006cb7713dec10368e699abc4367e5faa334c9a5

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