CVE-2026-68478: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: memstick: ms_block: reject a card that reports too many blocks msb_ftl_initialize() computes the zone count from the card block count with no bound: msb->zone_count = msb->block_count / MS_BLOCKS_IN_ZONE; ... for (i = 0; i < msb->zone_count; i++) msb->free_block_count[i] = MS_BLOCKS_IN_ZONE; msb->block_count is a card value. msb_read_boot_blocks() reads number_of_blocks from the card boot page and byte swaps it. free_block_count is a fixed int[MS_MAX_ZONES]. MS_MAX_ZONES is 16, so the valid indices are 0 to 15. The init loop above indexes it by zone_count. msb_mark_block_used() and msb_mark_block_unused() index it by pba / MS_BLOCKS_IN_ZONE, for pba up to block_count - 1. A card may report up to 65535 blocks. A block_count above 8192 (MS_MAX_ZONES * MS_BLOCKS_IN_ZONE) lets the pba index reach 16. That writes past free_block_count[] and corrupts struct msb_data. A larger count runs the init loop past the end too. A real Memory Stick has at most 16 zones. So it has at most 8192 blocks. msb_ftl_initialize() now rejects a card that reports more than MS_MAX_ZONES * MS_BLOCKS_IN_ZONE blocks.

Metrics

EPSS Probability

0.21%

11.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < a4b9961efe8640f50800811b4a2b2046b3dc2ccc; >= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < 8937b11f1c3896e066c3fb07387ba17bc8c50b8a; >= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < f1c675ecf6e5ad02722f0019f729d8bb588d502e; >= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < d5db3439ee8d1c165a09a47e984c4ba508c130df; >= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < b86666ac4009a252501cc17242582a7ec9ed976e; >= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < 39151f0708c84221e94cdd6aa070aba5d7cb1c01; >= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < 47f0c7d856c67c9935546d2644f18c0d0131b449; >= 0ab30494bc4f3bc1ea4659b7c5d97c5218554a63, < 718178f524b98bc920d74bc771aed823c8b81425
Linux	Linux	3.12

References

Timeline

Published: Aug 15, 2026
Last Modified: Aug 17, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-68478?

In the Linux kernel, the following vulnerability has been resolved: memstick: ms_block: reject a card that reports too many blocks msb_ftl_initialize() computes the zone count from the card block count with no bound: msb->zone_count = msb->block_count / MS_BLOCKS_IN_ZONE; ... for (i = 0; i < msb->zone_count; i++) msb->free_block_count[i] = MS_BLOCKS_IN_ZONE; msb->block_count is a card value. msb_read_boot_blocks() reads number_of_blocks from the card boot page and byte swaps it. free_block_count is a fixed int[MS_MAX_ZONES]. MS_MAX_ZONES is 16, so the valid indices are 0 to 15. The init loop above indexes it by zone_count. msb_mark_block_used() and msb_mark_block_unused() index it by pba / MS_BLOCKS_IN_ZONE, for pba up to block_count - 1. A card may report up to 65535 blocks. A block_count above 8192 (MS_MAX_ZONES * MS_BLOCKS_IN_ZONE) lets the pba index reach 16. That writes past free_block_count[] and corrupts struct msb_data. A larger count runs the init loop past the end too. A real Memory Stick has at most 16 zones. So it has at most 8192 blocks. msb_ftl_initialize() now rejects a card that reports more than MS_MAX_ZONES * MS_BLOCKS_IN_ZONE blocks.

How severe is CVE-2026-68478?

Severity scoring for CVE-2026-68478 is pending analysis. The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-68478?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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