CVE-2026-64157: Undefined Security Weakness

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

netfs: Fix partial invalidation of streaming-write folio

In netfs_invalidate_folio(), if the region of a partial invalidation overlaps the front (but not all) of a dirty write cached in a streaming write page (dirty, but not uptodate, with the dirty region tracked by a netfs_folio struct), the function modifies the dirty region - but incorrectly as it moves the region forward by setting the start to the start, not the end, of the invalidation region.

Fix this by setting finfo->dirty_offset to the end of the invalidation region (iend).