CVE-2026-74738regmap: sdw-mbq: don't call an unset readable_reg callback
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Aug 26, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69 before 6cf600b276a55a6481462830607a611f32e737c0; from 5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69 before 5bd8e897ecf558507142f4553e4526adfc1d6482; from 5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69 before 00268f9452d2a0d660aa9c1bb0ca07a994af6a4f | CNA record |
References
- https://git.kernel.org/stable/c/6cf600b276a55a6481462830607a611f32e737c0
- https://git.kernel.org/stable/c/5bd8e897ecf558507142f4553e4526adfc1d6482
- https://git.kernel.org/stable/c/00268f9452d2a0d660aa9c1bb0ca07a994af6a4f
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.