CVE-2025-68773: spi: fsl-cpm: Check length parity before switching to 16 bit mode

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-13 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: spi: fsl-cpm: Check length parity before switching to 16 bit mode Commit fc96ec826bce ("spi: fsl-cpm: Use 16 bit mode for large transfers with even size") failed to make sure that the size is really even before switching to 16 bit mode. Until recently the problem went unnoticed because kernfs uses a pre-allocated bounce buffer of size PAGE_SIZE for reading EEPROM. But commit 8ad6249c51d0 ("eeprom: at25: convert to spi-mem API") introduced an additional dynamically allocated bounce buffer whose size is exactly the size of the transfer, leading to a buffer overrun in the fsl-cpm driver when that size is odd. Add the missing length parity verification and remain in 8 bit mode when the length is not even.

Affected products

Linux kernel: from 5.10.181 before 5.10.248; from 5.15.114 before 5.15.198; from 6.1.29 before 6.1.160; from 4.14.316 before 4.15; from 4.19.284 before 4.20; from 5.4.244 before 5.5 — fixed in 4.15, 4.20, 5.10.248, 5.15.198, 5.5, 6.1.160

How to fix

Upgrade to a fixed version: Linux kernel 4.15, 4.20, 5.10.248, 5.15.198. Check the vendor advisory for mitigations.

References

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