CVE-2026-64322

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

udf: validate sparing table length as an entry count, not a byte count

udf_load_sparable_map() accepts a sparing table when

sizeof(*st) + le16_to_cpu(st->reallocationTableLen) > sb->s_blocksize

is false, i.e. it treats reallocationTableLen as a number of BYTES that
must fit in the block. But the table is walked as an array of 8-byte
sparingEntry elements:

for (i = 0; i reallocationTableLen); i++) {
struct sparingEntry *entry = &st->mapEntry[i];
... entry->origLocation ...
}

in udf_get_pblock_spar15() and udf_relocate_blocks(). A
reallocationTableLen of N therefore passes the check whenever
sizeof(*st) + N mapEntry[] is an out-of-bounds
write.

Validate reallocationTableLen as the entry count it is, with
struct_size().