« Back to list

CVE-2026-74738

Status: ReceivedUnscored—

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.

Read full descriptionShow less

Treat a missing callback the way the rest of regmap does and poll.

CVSS

NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux KernelAI

References

Raw JSON (NVD)

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