{"id":"CVE-2026-98848","title":"rtc: ac100: Assign .num before accessing .hws","summary":"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 'struct cl…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < 6bb55381daf1a1bed0657189a1396e7467712525","Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < 160619b38707241e22569f9c983a4b3d0890996a","Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < ad1bf77039cba83373bf1eff3784655e3e3ed2ab","Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < 6a4117eee82dd85f11bf898bf66026764011eeb6","Linux 6.6"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:50:47.105Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98848","references":[{"url":"https://git.kernel.org/stable/c/6bb55381daf1a1bed0657189a1396e7467712525"},{"url":"https://git.kernel.org/stable/c/160619b38707241e22569f9c983a4b3d0890996a"},{"url":"https://git.kernel.org/stable/c/ad1bf77039cba83373bf1eff3784655e3e3ed2ab"},{"url":"https://git.kernel.org/stable/c/6a4117eee82dd85f11bf898bf66026764011eeb6"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.464Z","slug":"CVE-2026-98848","body":"## Overview\n\nIn 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 'struct clk_hw_onecell_data'\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's\nbehaviour is unchanged.\n\n## Affected\n\n- `Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < 6bb55381daf1a1bed0657189a1396e7467712525`\n- `Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < 160619b38707241e22569f9c983a4b3d0890996a`\n- `Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < ad1bf77039cba83373bf1eff3784655e3e3ed2ab`\n- `Linux >= f316cdff8d677db9ad9c90acb44c4cd535b0ee27 < 6a4117eee82dd85f11bf898bf66026764011eeb6`\n- `Linux 6.6`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}