{"id":"CVE-2026-99159","aliases":[],"title":"ring-buffer: Fix the sub-buffer array base in rb_meta_subbuf_idx()","titleSource":"Linux","descriptionSource":"Linux","products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"b14d032973d4e6c36e025e96ea3437de53d072d9","status":"affected","lessThan":"2f1248b728b56d583ea454fedf239550c49f7b18","versionType":"git"},{"version":"b14d032973d4e6c36e025e96ea3437de53d072d9","status":"affected","lessThan":"7469b3585ef5f65840d467d2caa811a9098c84b9","versionType":"git"},{"version":"b14d032973d4e6c36e025e96ea3437de53d072d9","status":"affected","lessThan":"25132363c723afc39aace8b098f547ab4a0ea759","versionType":"git"}],"defaultStatus":"unaffected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99159"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99159"}],"remediation":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix the sub-buffer array base in rb_meta_subbuf_idx()\n\nOn a persistent ring buffer, rb_meta_subbuf_idx() can return an index one\nsub-buffer too high.  rb_setup_ids_meta_page() then fills subbuf_ids[]\nshifted by one and leaves subbuf_ids[0] NULL, which __rb_map_vma()\ndereferences when userspace maps trace_pipe_raw.  rb_update_meta_reader()\nwrites two such indices into meta->buffers[], which rb_cpu_meta_valid()\nwould reject on the next boot, discarding the previous boot's trace.\n\nA CPU's sub-buffer array starts after its meta header and the nr_subbufs\nintegers that follow, aligned up to a sub-buffer.  rb_meta_subbuf_idx()\ninverts that calculation but skips only the integers, not the header, so\nits base is one sub-buffer low whenever the omitted header size crosses\nthe alignment boundary.\n\nInvert the calculation with rb_subbufs_from_meta() rather than repeating\nit.  rb_range_buffer() maps an index back to an address through the same\nhelper, so the two directions can no longer disagree.","severity":"unknown","score":null,"published":"2026-10-28T10:35:12.520Z","modified":"2026-10-28T10:35:12.520Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://git.kernel.org/stable/c/2f1248b728b56d583ea454fedf239550c49f7b18","https://git.kernel.org/stable/c/7469b3585ef5f65840d467d2caa811a9098c84b9","https://git.kernel.org/stable/c/25132363c723afc39aace8b098f547ab4a0ea759"],"sources":[{"name":"CVE","id":"CVE-2026-99159","modified":"2026-10-28T10:35:12.520Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-99159"}],"assessments":[],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T19:50:56.313Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}