FKIE_CVE-2026-74738

Vulnerability from fkie_nvd - Published: 2026-08-26 15:16 - Updated: 2026-08-26 15:16
Severity
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/00268f9452d2a0d660aa9c1bb0ca07a994af6a4f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5bd8e897ecf558507142f4553e4526adfc1d6482
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6cf600b276a55a6481462830607a611f32e737c0
Impacted products
Vendor Product Version
To clipboard 

{
  "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\u0027t 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."
    }
  ],
  "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"
}



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