{"id":"CVE-2026-89771","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89771","summary":"ring-buffer: Fix subbuf resize race with ring buffer readers","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix subbuf resize race with ring buffer readers\n\ntrace_buffer subbuf_size is read lockless in ring_buffer_read_page() and\nring_buffer_read_start(), while it can simultaneously be resized with\nring_buffer_subbuf_order_set().\n\nInstead of trace_buffer::subbuf_size, use bpage::order in\nring_buffer_read_start() and ring_buffer_read_page().\n\nIn ring_buffer_read_start(), even with resize_disabled, there is still a\npossibility of a race with a buffer modification. Hold the trace_buffer\nmutex to synchronise with any pending ring buffer order modification.\n\ntrace_buffer::subbuf_size is now actually useless, remove it. Also,\ncreate accessors rb_subbuf_capacity() and rb_page_capacity() which\nreturn the actual size available for storing events, while\nrb_subbuf_size() returns the actual subbuf page-size.","published":"2026-09-11T19:47:10.381Z","modified":"2026-09-14T03:46:33.688886139Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.12.109"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27"},{"type":"WEB","url":"https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89771.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89771"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:46:33.688886139Z"}}