CVE-2026-74738
In the Linux kernel, the following vulnerability has been resolved: regmap: sdw-mbq: don't call an unset readable_reg callback regmap_sdw_mbq_poll_busy() decides whether to poll the Function Busy…
Overview
CVE-2026-74738 is a known-severity vulnerability. It was published on August 26, 2026.
Technical description
In the Linux kernel, the following vulnerability has been resolved:
regmap: sdw-mbq: don't call an unset readable_reg callback
regmap_sdw_mbq_poll_busy() decides whether to poll the Function Busy bit
by calling ctx->readable_reg(), which is a straight copy of
config->readable_reg. That callback is optional: regmap_readable() treats
a NULL ->readable_reg as "every register is readable", and drivers rely on
that. es9356 and tac5xx2-sdw both build an MBQ regmap without one.
Since commit ca1b11b36d82 ("regmap: sdw-mbq: Allow defers on undeferrable
controls") the poll runs on every -ENODATA, not only for Controls the
driver marked deferrable, so any of those devices answering
COMMAND_IGNORED takes the kernel through a NULL function pointer.
Treat a missing callback the way the rest of regmap does and poll.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2026-74738?
CVE-2026-74738 is a known-severity vulnerability. It was published on August 26, 2026.
How severe is CVE-2026-74738?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-74738?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-74738?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-74738 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.