{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74738", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.930Z", "datePublished": "2026-08-26T14:36:51.136Z", "dateUpdated": "2026-08-26T14:36:51.136Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-26T14:36:51.136Z"}, "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": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/base/regmap/regmap-sdw-mbq.c"], "versions": [{"version": "5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69", "lessThan": "6cf600b276a55a6481462830607a611f32e737c0", "status": "affected", "versionType": "git"}, {"version": "5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69", "lessThan": "5bd8e897ecf558507142f4553e4526adfc1d6482", "status": "affected", "versionType": "git"}, {"version": "5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69", "lessThan": "00268f9452d2a0d660aa9c1bb0ca07a994af6a4f", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/base/regmap/regmap-sdw-mbq.c"], "versions": [{"version": "6.14", "status": "affected"}, {"version": "0", "lessThan": "6.14", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.46", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.10", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "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"}]}]}], "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"}], "title": "regmap: sdw-mbq: don't call an unset readable_reg callback", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/base/regmap/regmap-sdw-mbq.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "6cf600b276a55a6481462830607a611f32e737c0", "status": "affected", "version": "5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69", "versionType": "git"}, {"lessThan": "5bd8e897ecf558507142f4553e4526adfc1d6482", "status": "affected", "version": "5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69", "versionType": "git"}, {"lessThan": "00268f9452d2a0d660aa9c1bb0ca07a994af6a4f", "status": "affected", "version": "5bc493bf0c37c157bf2eb364e55a1c6f8bc43a69", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/base/regmap/regmap-sdw-mbq.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.14"}, {"lessThan": "6.14", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.46", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.10", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-74738", "lastModified": "2026-08-26T15:16:52.480", "metrics": {}, "published": "2026-08-26T15:16:52.480", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/00268f9452d2a0d660aa9c1bb0ca07a994af6a4f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5bd8e897ecf558507142f4553e4526adfc1d6482"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6cf600b276a55a6481462830607a611f32e737c0"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: regmap: sdw-mbq: don't call an unset readable_reg callback", "id": "2524446", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2524446"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nregmap: sdw-mbq: don't call an unset readable_reg callback\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.\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.\nTreat a missing callback the way the rest of regmap does and poll.", "A flaw was found in the `regmap: sdw-mbq` component of the Linux kernel. This vulnerability occurs when the `regmap_sdw_mbq_poll_busy()` function attempts to call an unset `readable_reg` callback. If a device responds with `COMMAND_IGNORED`, it can lead to a NULL function pointer dereference. This could potentially result in a system crash or denial of service."], "name": "CVE-2026-74738", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-26T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74738\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74738\nhttps://lore.kernel.org/linux-cve-announce/2026082656-CVE-2026-74738-4552@gregkh/T"], "threat_severity": "Moderate"}