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) >…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.17% probability · 6th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/04f4599a9efb90992d072a814960edf0cd62805dPatch
- https://git.kernel.org/stable/c/0a9b79a951cfd70a9d31ca01ae2d08a20bb730e9Patch
- https://git.kernel.org/stable/c/2a219acb2ce674d99bbd1b7b35ed8c384dac7200Patch
- https://git.kernel.org/stable/c/2d726135099313958f8975532a2e15322ff150cePatch
- https://git.kernel.org/stable/c/3ec997bd5508e9b25210b5bbec89031629cdb093Patch
- https://git.kernel.org/stable/c/7285276aa50d2839afb5957ffd491ad282dc8f72Patch
- https://git.kernel.org/stable/c/7f7774b9da0ef17b87bfa238cf966ad0b3376150Patch
- https://git.kernel.org/stable/c/eeb0f3e193f8e523d03e4c9e084f6b4875f50e8ePatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.