{"id":"CVE-2026-98848","summary":"rtc: ac100: Assign .num before accessing .hws","details":"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 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.","modified":"2026-10-19T02:47:34.992355847Z","published":"2026-10-18T15:50:47.105Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98848.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/160619b38707241e22569f9c983a4b3d0890996a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6a4117eee82dd85f11bf898bf66026764011eeb6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6bb55381daf1a1bed0657189a1396e7467712525"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ad1bf77039cba83373bf1eff3784655e3e3ed2ab"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98848.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98848"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27"},{"fixed":"6bb55381daf1a1bed0657189a1396e7467712525"},{"fixed":"160619b38707241e22569f9c983a4b3d0890996a"},{"fixed":"ad1bf77039cba83373bf1eff3784655e3e3ed2ab"},{"fixed":"6a4117eee82dd85f11bf898bf66026764011eeb6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98848.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.6.0"},{"fixed":"6.12.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.56"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98848.json"}}],"schema_version":"1.9.0"}