FKIE_CVE-2026-64502

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-11-03 18:15
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: iio: adc: ad_sigma_delta: fix clear_pending_event for registerless devices ad_sigma_delta_clear_pending_event() falls through to the status register read path for devices with has_registers = false and no rdy_gpiod. For such devices, ad_sd_read_reg() skips the address byte entirely and clocks raw MISO bytes with no address phase — making it byte-for-byte identical to reading conversion data. If a pending conversion result is present, this partially consumes it and corrupts the data stream for the subsequent ad_sd_read_reg() call in ad_sigma_delta_single_conversion(). Furthermore, with num_resetclks = 0 on these devices, data_read_len evaluates to 0. If the clocked byte has bit 7 clear, pending_event is set and the code attempts memset(data + 2, 0xff, 0 - 1), overflowing to SIZE_MAX and corrupting the heap. Fix by returning 0 immediately when neither rdy_gpiod nor has_registers is set. This is safe for all current registerless devices: ad7191 and ad7780 (with powerdown GPIO) are reset between conversions by CS deassertion, so there is no stale result to drain; ad7780 (without powerdown GPIO) and max11205 are continuously-converting and cycle ~DRDY at the output data rate regardless of whether the previous result was read, so the next falling edge fires naturally. A future registerless device that holds ~DRDY asserted until data is read would be broken by this early return and would require either num_resetclks set or a rdy-gpio. The same heap corruption is reachable on any device with rdy_gpiod set but num_resetclks = 0: if the GPIO indicates a pending event, the drain path executes memset(data + 2, 0xff, 0 - 1) regardless of has_registers. Add an explicit data_read_len == 0 guard after the pending event check; the stale result is then consumed by the first ad_sd_read_reg() call in ad_sigma_delta_single_conversion().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3394e0b3328422431cadaf314fa58d3717ed4936
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3bceb26dfaf7ba805b459e41c1d0ba916862dade
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/91bc6767a4f55dc470d8a56b55b9f2ea09094efe
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iio/adc/ad_sigma_delta.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3394e0b3328422431cadaf314fa58d3717ed4936",
              "status": "affected",
              "version": "132d44dc6966c1cf841ffe0f6f048165687e870b",
              "versionType": "git"
            },
            {
              "lessThan": "3bceb26dfaf7ba805b459e41c1d0ba916862dade",
              "status": "affected",
              "version": "132d44dc6966c1cf841ffe0f6f048165687e870b",
              "versionType": "git"
            },
            {
              "lessThan": "91bc6767a4f55dc470d8a56b55b9f2ea09094efe",
              "status": "affected",
              "version": "132d44dc6966c1cf841ffe0f6f048165687e870b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/iio/adc/ad_sigma_delta.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": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "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\niio: adc: ad_sigma_delta: fix clear_pending_event for registerless devices\n\nad_sigma_delta_clear_pending_event() falls through to the status register\nread path for devices with has_registers = false and no rdy_gpiod. For\nsuch devices, ad_sd_read_reg() skips the address byte entirely and clocks\nraw MISO bytes with no address phase \u2014 making it byte-for-byte identical\nto reading conversion data. If a pending conversion result is present,\nthis partially consumes it and corrupts the data stream for the subsequent\nad_sd_read_reg() call in ad_sigma_delta_single_conversion().\n\nFurthermore, with num_resetclks = 0 on these devices, data_read_len\nevaluates to 0. If the clocked byte has bit 7 clear, pending_event is set\nand the code attempts memset(data + 2, 0xff, 0 - 1), overflowing to\nSIZE_MAX and corrupting the heap.\n\nFix by returning 0 immediately when neither rdy_gpiod nor has_registers\nis set. This is safe for all current registerless devices: ad7191 and\nad7780 (with powerdown GPIO) are reset between conversions by CS\ndeassertion, so there is no stale result to drain; ad7780 (without\npowerdown GPIO) and max11205 are continuously-converting and cycle ~DRDY\nat the output data rate regardless of whether the previous result was\nread, so the next falling edge fires naturally.\n\nA future registerless device that holds ~DRDY asserted until data is read\nwould be broken by this early return and would require either\nnum_resetclks set or a rdy-gpio.\n\nThe same heap corruption is reachable on any device with rdy_gpiod set\nbut num_resetclks = 0: if the GPIO indicates a pending event, the drain\npath executes memset(data + 2, 0xff, 0 - 1) regardless of has_registers.\nAdd an explicit data_read_len == 0 guard after the pending event check;\nthe stale result is then consumed by the first ad_sd_read_reg() call in\nad_sigma_delta_single_conversion()."
    }
  ],
  "id": "CVE-2026-64502",
  "lastModified": "2026-11-03T18:15:39.353",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-25T10:17:36.200",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3394e0b3328422431cadaf314fa58d3717ed4936"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3bceb26dfaf7ba805b459e41c1d0ba916862dade"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/91bc6767a4f55dc470d8a56b55b9f2ea09094efe"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}



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