CVE-2026-43380: hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-08 · updated 2026-06-17
Weakness: CWE-125

Description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read The q54sj108a2_debugfs_read function suffers from a stack buffer overflow due to incorrect arguments passed to bin2hex(). The function currently passes 'data' as the destination and 'data_char' as the source. Because bin2hex() converts each input byte into two hex characters, a 32-byte block read results in 64 bytes of output. Since 'data' is only 34 bytes (I2C_SMBUS_BLOCK_MAX + 2), this writes 30 bytes past the end of the buffer onto the stack. Additionally, the arguments were swapped: it was reading from the zero-initialized 'data_char' and writing to 'data', resulting in all-zero output regardless of the actual I2C read. Fix this by: 1. Expanding 'data_char' to 66 bytes to safely hold the hex output. 2. Correcting the bin2hex() argument order and using the actual read count. 3. Using a pointer to select the correct output buffer for the final simple_read_from_buffer call.

Affected products

Linux kernel: from 5.11 before 5.15.203; from 5.16 before 6.1.167; from 6.2 before 6.6.130; from 6.7 before 6.12.78; from 6.13 before 6.18.19; from 6.19 before 6.19.9 — fixed in 5.15.203, 6.1.167, 6.12.78, 6.18.19, 6.19.9, 6.6.130

How to fix

Upgrade to a fixed version: Linux kernel 5.15.203, 6.1.167, 6.12.78, 6.18.19. Check the vendor advisory for mitigations.

References

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