PT-2026-64543 · Linux · Linux

CVE-2026-64322

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Published

2026-07-25

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Updated

2026-07-25

None

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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 < le16 to cpu(st->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 <= blocksize, yet the consumers index sizeof(*st) + N * sizeof(struct sparingEntry) bytes -- up to ~8x the block. On a crafted UDF image this is an out-of-bounds read in udf get pblock spar15(); udf relocate blocks() additionally feeds the same length to udf update tag(), whose crc itu t() reads far past the block, and its memmove() through st->mapEntry[] is an out-of-bounds write.
Validate reallocationTableLen as the entry count it is, with struct size().
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Related Identifiers

CVE-2026-64322

Affected Products

Linux