CVE-2026-64322
Analyzed
Analyzed - Analysis Complete
Buffer Overflow in Linux Kernel UDF Filesystem
Vulnerability report for CVE-2026-64322, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-07-25
Last updated on: 2026-09-04
Assigner: kernel.org
Description
Description
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().
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | 3.5 |
| linux | linux_kernel | 3.5 |
| linux | linux_kernel | 3.5 |
| linux | linux_kernel | 3.5 |
| linux | linux_kernel | From 5.11 (inc) to 5.15.212 (exc) |
| linux | linux_kernel | From 5.16 (inc) to 6.1.178 (exc) |
| linux | linux_kernel | From 6.2 (inc) to 6.6.145 (exc) |
| linux | linux_kernel | From 6.7 (inc) to 6.12.96 (exc) |
| linux | linux_kernel | From 6.13 (inc) to 6.18.39 (exc) |
| linux | linux_kernel | From 6.19 (inc) to 7.1.4 (exc) |
| linux | linux_kernel | From 2.6.32.60 (inc) to 2.6.33 (exc) |
| linux | linux_kernel | From 2.6.34.14 (inc) to 2.6.35 (exc) |
| linux | linux_kernel | From 3.0.37 (inc) to 3.1 (exc) |
| linux | linux_kernel | From 3.2.23 (inc) to 3.3 (exc) |
| linux | linux_kernel | From 3.4.5 (inc) to 3.5 (exc) |
| linux | linux_kernel | From 3.5.1 (inc) to 5.10.261 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-787 | The product writes data past the end, or before the beginning, of the intended buffer. |
