CVE-2026-93095

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

hfsplus: validate thread record before delete key rebuild

hfsplus_delete_cat() is called with str == NULL when the last open

reference to an unlinked HFS+ hardlink backing inode is closed. In that

case, the function finds the catalog thread by CNID and rebuilds the

catalog key from thread.nodeName.

That reconstruction path reads thread.nodeName.length directly from the

catalog B-tree into fd.search_key and then copies length * 2 bytes into

fd.search_key->cat.name.unicode. It does not first check that the found

record is a thread record or that its size matches the thread name.

A corrupted image can therefore provide an oversized thread name length

and make hfs_bnode_read() write past the catalog search-key allocation.

Read the CNID record through hfsplus_brec_read_cat(), which bounds the

record read to sizeof(hfsplus_cat_entry) and verifies that a thread

record's size exactly matches nodeName.length. Together, these checks

ensure an accepted thread name fits HFSPLUS_MAX_STRLEN. Reject non-thread

records before building the delete key from the validated thread name.

Share the thread-record-type helper between hfsplus_find_cat() and

hfsplus_delete_cat().