SB20260827136 - NULL pointer dereference in Linux kernel base regmap driver

Description

This security bulletin contains information about 1 vulnerability.

1) NULL pointer dereference (CVE-ID: CVE-2026-74738)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local attacker to cause a denial of service.

The vulnerability exists due to a NULL function pointer dereference in regmap_sdw_mbq_poll_busy() in the regmap sdw-mbq component when handling devices that answer COMMAND_IGNORED and no readable_reg callback is set. A local attacker can trigger the code path to cause a denial of service.

The issue occurs because a missing readable_reg callback is treated incorrectly during Function Busy polling after an -ENODATA condition.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/00268f9452d2a0d660aa9c1bb0ca07a994af6a4f
• https://git.kernel.org/stable/c/5bd8e897ecf558507142f4553e4526adfc1d6482
• https://git.kernel.org/stable/c/6cf600b276a55a6481462830607a611f32e737c0