{"id":"CVE-2026-98848","state":"PUBLISHED","title":"rtc: ac100: Assign .num before accessing .hws","description":"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.","publishedAt":"2026-10-18T15:50:47.105Z","updatedAt":"2026-10-21T12:57:28.688Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"6bb55381daf1a1bed0657189a1396e7467712525","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"160619b38707241e22569f9c983a4b3d0890996a","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"ad1bf77039cba83373bf1eff3784655e3e3ed2ab","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"6a4117eee82dd85f11bf898bf66026764011eeb6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/rtc/rtc-ac100.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.6","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/rtc/rtc-ac100.c"]}],"references":["https://git.kernel.org/stable/c/e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef","https://git.kernel.org/stable/c/6bb55381daf1a1bed0657189a1396e7467712525","https://git.kernel.org/stable/c/160619b38707241e22569f9c983a4b3d0890996a","https://git.kernel.org/stable/c/ad1bf77039cba83373bf1eff3784655e3e3ed2ab","https://git.kernel.org/stable/c/6a4117eee82dd85f11bf898bf66026764011eeb6"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98848.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98848","state":"PUBLISHED","datePublished":"2026-10-18T15:50:47.105Z","dateUpdated":"2026-10-21T12:57:28.688Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.373Z"},"containers":{"cna":{"title":"rtc: ac100: Assign .num before accessing .hws","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 '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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"6bb55381daf1a1bed0657189a1396e7467712525","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"160619b38707241e22569f9c983a4b3d0890996a","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"ad1bf77039cba83373bf1eff3784655e3e3ed2ab","versionType":"git"},{"version":"f316cdff8d677db9ad9c90acb44c4cd535b0ee27","status":"affected","lessThan":"6a4117eee82dd85f11bf898bf66026764011eeb6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/rtc/rtc-ac100.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.6","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/rtc/rtc-ac100.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e77c5fc1f39fdb06ecd1f55b101eea1e1db2ffef"},{"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:57:28.688Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}