Advisory [CVE-2026-63936] fix unchecked return value in mt6358_read_imp

In the Linux kernel, the following vulnerability has been resolved: iio: adc: mt6359: fix unchecked return value in mt6358_read_imp In mt6358_read_imp(), the variable val_v is passed to regmap_read() but the return value is not checked.

If the read fails, val_v remains uninitialized and its random stack content is subsequently reported as a measurement result. Initialize val_v to zero to ensure a predictable value is reported in case of bus failure and to prevent potential stack data leakage.

This also satisfies static analyzers that might otherwise flag the variable as used uninitialized. A flaw was found in the Linux kernel's MediaTek MT6359 Analog-to-Digital Converter (ADC) driver.

The `mt6358_read_imp()` function does not properly check the return value of a read operation. If the read fails, an uninitialized variable is used, which can lead to the leakage of sensitive information from the kernel's memory (stack data leakage).

This vulnerability could allow a local attacker to gain access to potentially confidential data. Red Hat severity: not rated.

Weakness: CWE-824. Red Hat lists Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9 as not affected.