{"id":"CVE-2026-74738","summary":"regmap: sdw-mbq: don't call an unset readable_reg callback","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nregmap: sdw-mbq: don't call an unset readable_reg callback\n\nregmap_sdw_mbq_poll_busy() decides whether to poll the Function Busy bit\nby calling ctx-\u003ereadable_reg(), which is a straight copy of\nconfig-\u003ereadable_reg. That callback is optional: regmap_readable() treats\na NULL -\u003ereadable_reg as \"every register is readable\", and drivers rely on\nthat. es9356 and tac5xx2-sdw both build an MBQ regmap without one.\n\nSince commit ca1b11b36d82 (\"regmap: sdw-mbq: Allow defers on undeferrable\ncontrols\") the poll runs on every -ENODATA, not only for Controls the\ndriver marked deferrable, so any of those devices answering\nCOMMAND_IGNORED takes the kernel through a NULL function pointer.\n\nTreat a missing callback the way the rest of regmap does and poll.","modified":"2026-08-28T11:48:23.508498405Z","published":"2026-08-26T14:36:51.136Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74738.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/00268f9452d2a0d660aa9c1bb0ca07a994af6a4f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5bd8e897ecf558507142f4553e4526adfc1d6482"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6cf600b276a55a6481462830607a611f32e737c0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74738.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74738"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69"},{"fixed":"6cf600b276a55a6481462830607a611f32e737c0"},{"fixed":"5bd8e897ecf558507142f4553e4526adfc1d6482"},{"fixed":"00268f9452d2a0d660aa9c1bb0ca07a994af6a4f"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74738.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.14.0"},{"fixed":"6.18.46"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74738.json"}}],"schema_version":"1.9.0"}