{"cve":"CVE-2026-99159","nvd":{"published":"2026-10-28T11:17:36.160","modified":"2026-10-28T11:17:36.160","status":"Received","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/25132363c723afc39aace8b098f547ab4a0ea759","https://git.kernel.org/stable/c/2f1248b728b56d583ea454fedf239550c49f7b18","https://git.kernel.org/stable/c/7469b3585ef5f65840d467d2caa811a9098c84b9"],"products":[],"source":"nvd","synced_at":"2026-10-28T11:37:51.394563875+00:00"},"epss":null,"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}