CVE-2026-74738 in Linux
Resumen
por MITRE • 2026-08-26
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.
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