FKIE_CVE-2026-98848

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-18 16:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: rtc: ac100: Assign .num before accessing .hws Commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") annotated the hws member of 'struct clk_hw_onecell_data' with __counted_by, which informs the bounds sanitizer (UBSAN_BOUNDS) about the number of elements in .hws[], so that it can warn when .hws[] is accessed out of bounds. As noted in that change, the __counted_by member must be initialized with the number of elements before the first array access happens, otherwise there will be a warning from each access prior to the initialization because the number of elements is zero. This occurs in ac100_rtc_register_clks() due to .num being assigned only after every clkout clock has been stored in .hws[]. With CONFIG_UBSAN_BOUNDS and a compiler that implements __counted_by (GCC 15.1+ or Clang 20.1+), this triggers an array-index-out-of-bounds report during probe, and with CONFIG_UBSAN_TRAP the first store traps. Initialize .num with AC100_CLKOUT_NUM, the number of elements .hws[] was allocated with, right after the allocation. That is the value the loop counter ends up at on the success path anyway, so the provider's behaviour is unchanged.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/160619b38707241e22569f9c983a4b3d0890996a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6a4117eee82dd85f11bf898bf66026764011eeb6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6bb55381daf1a1bed0657189a1396e7467712525
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ad1bf77039cba83373bf1eff3784655e3e3ed2ab
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/rtc/rtc-ac100.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6bb55381daf1a1bed0657189a1396e7467712525",
              "status": "affected",
              "version": "f316cdff8d677db9ad9c90acb44c4cd535b0ee27",
              "versionType": "git"
            },
            {
              "lessThan": "160619b38707241e22569f9c983a4b3d0890996a",
              "status": "affected",
              "version": "f316cdff8d677db9ad9c90acb44c4cd535b0ee27",
              "versionType": "git"
            },
            {
              "lessThan": "ad1bf77039cba83373bf1eff3784655e3e3ed2ab",
              "status": "affected",
              "version": "f316cdff8d677db9ad9c90acb44c4cd535b0ee27",
              "versionType": "git"
            },
            {
              "lessThan": "6a4117eee82dd85f11bf898bf66026764011eeb6",
              "status": "affected",
              "version": "f316cdff8d677db9ad9c90acb44c4cd535b0ee27",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/rtc/rtc-ac100.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc6",
              "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\nrtc: ac100: Assign .num before accessing .hws\n\nCommit f316cdff8d67 (\"clk: Annotate struct clk_hw_onecell_data with\n__counted_by\") annotated the hws member of \u0027struct clk_hw_onecell_data\u0027\nwith __counted_by, which informs the bounds sanitizer (UBSAN_BOUNDS)\nabout the number of elements in .hws[], so that it can warn when .hws[]\nis accessed out of bounds. As noted in that change, the __counted_by\nmember must be initialized with the number of elements before the first\narray access happens, otherwise there will be a warning from each access\nprior to the initialization because the number of elements is zero.\nThis occurs in ac100_rtc_register_clks() due to .num being assigned only\nafter every clkout clock has been stored in .hws[]. With\nCONFIG_UBSAN_BOUNDS and a compiler that implements __counted_by (GCC\n15.1+ or Clang 20.1+), this triggers an array-index-out-of-bounds report\nduring probe, and with CONFIG_UBSAN_TRAP the first store traps.\n\nInitialize .num with AC100_CLKOUT_NUM, the number of elements .hws[] was\nallocated with, right after the allocation. That is the value the loop\ncounter ends up at on the success path anyway, so the provider\u0027s\nbehaviour is unchanged."
    }
  ],
  "id": "CVE-2026-98848",
  "lastModified": "2026-10-18T16:17:39.163",
  "metrics": {},
  "published": "2026-10-18T16:17:39.163",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/160619b38707241e22569f9c983a4b3d0890996a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6a4117eee82dd85f11bf898bf66026764011eeb6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6bb55381daf1a1bed0657189a1396e7467712525"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ad1bf77039cba83373bf1eff3784655e3e3ed2ab"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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