{"id":"CVE-2026-74738","state":"PUBLISHED","title":"regmap: sdw-mbq: don't call an unset readable_reg callback","description":"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->readable_reg(), which is a straight copy of\nconfig->readable_reg. That callback is optional: regmap_readable() treats\na NULL ->readable_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.","publishedAt":"2026-08-26T14:36:51.136Z","updatedAt":"2026-08-26T14:36:51.136Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69","status":"affected","lessThan":"6cf600b276a55a6481462830607a611f32e737c0","versionType":"git"},{"version":"5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69","status":"affected","lessThan":"5bd8e897ecf558507142f4553e4526adfc1d6482","versionType":"git"},{"version":"5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69","status":"affected","lessThan":"00268f9452d2a0d660aa9c1bb0ca07a994af6a4f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/base/regmap/regmap-sdw-mbq.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.18.46","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.10","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/base/regmap/regmap-sdw-mbq.c"]}],"references":["https://git.kernel.org/stable/c/6cf600b276a55a6481462830607a611f32e737c0","https://git.kernel.org/stable/c/5bd8e897ecf558507142f4553e4526adfc1d6482","https://git.kernel.org/stable/c/00268f9452d2a0d660aa9c1bb0ca07a994af6a4f"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74738.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74738","state":"PUBLISHED","datePublished":"2026-08-26T14:36:51.136Z","dateUpdated":"2026-08-26T14:36:51.136Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.930Z"},"containers":{"cna":{"title":"regmap: sdw-mbq: don't call an unset readable_reg callback","descriptions":[{"lang":"en","value":"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->readable_reg(), which is a straight copy of\nconfig->readable_reg. That callback is optional: regmap_readable() treats\na NULL ->readable_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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69","status":"affected","lessThan":"6cf600b276a55a6481462830607a611f32e737c0","versionType":"git"},{"version":"5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69","status":"affected","lessThan":"5bd8e897ecf558507142f4553e4526adfc1d6482","versionType":"git"},{"version":"5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69","status":"affected","lessThan":"00268f9452d2a0d660aa9c1bb0ca07a994af6a4f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/base/regmap/regmap-sdw-mbq.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.18.46","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.10","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/base/regmap/regmap-sdw-mbq.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/6cf600b276a55a6481462830607a611f32e737c0"},{"url":"https://git.kernel.org/stable/c/5bd8e897ecf558507142f4553e4526adfc1d6482"},{"url":"https://git.kernel.org/stable/c/00268f9452d2a0d660aa9c1bb0ca07a994af6a4f"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-26T14:36:51.136Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.18.46"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.1.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}