{"id":"CVE-2026-89771","revision":"d2a89e3f34544a2b92f44981f895a82c","records":[{"revision":"d2a89e3f34544a2b92f44981f895a82c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89771","aliases":[],"title":"ring-buffer: Fix subbuf resize race with ring buffer readers","description":"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.","state":0,"publishedAt":"2026-09-11T19:47:10.381+00:00","modifiedAt":"2026-10-19T08:52:24.715+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"kernel/trace/ring_buffer.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\n                            \"lessThan\": \"6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\n                            \"lessThan\": \"50f4a793c4ff24826efb0ac700989a5063cc53df\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\n                            \"lessThan\": \"0c7c517827a453128a8f58bfd849546a29813b27\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"f9b94daa542a8d2532f0930f01cd9aec2d19621b\",\n                            \"lessThan\": \"8a5f63637890f03177146efddaba5ec7a1b4d61f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"kernel/trace/ring_buffer.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.8\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.8\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9","https://git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df","https://git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27","https://git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89771","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89771","identifiers":["CVE-2026-89771"]},"retained":false,"historicalAffected":[]}],"coverage":[]}