{"id":"CVE-2026-53243","summary":"rseq: Fix using an uninitialized stack variable in rseq_exit_user_update()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nrseq: Fix using an uninitialized stack variable in rseq_exit_user_update()\n\nThere is an bug in which an uninitialized stack variable is used in\nrseq_exit_user_update() as reported by syzbot:\n\nBUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline]\n\nThe local variable:\n\n\tstruct rseq_ids ids = {\n\t\t.cpu_id\t = task_cpu(t),\n\t\t.mm_cid\t = task_mm_cid(t),\n\t\t.node_id = cpu_to_node(ids.cpu_id),\n\t};\n\nAccording to the C standard, the evaluation order of expressions in an\ninitializer list is indeterminately sequenced. The compiler (Clang, in\nthis KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before*\n`ids.cpu_id` is initialized with `task_cpu(t)`.\n\nThis is fixed by moving the assignment of ids.node_id outside the\nstructure initialization.","modified":"2026-07-15T01:49:11.661137021Z","published":"2026-06-25T08:39:37.794Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53243.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e12d20a63b61aaf9de4772effccf42cc9a003e58"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53243.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53243"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d242126fd21ab8f1631fdbc8589e43a9d4229f3b"},{"fixed":"e12d20a63b61aaf9de4772effccf42cc9a003e58"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"82f572449cfe75f12ea985986da60e11f308f77d"},{"fixed":"6d99479799c69c3cb588fcda19c81d8f61d64ecd"}]}],"versions":["v7.0.12","v7.0.11","v7.0.10"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53243.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.10"},{"fixed":"7.0.13"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53243.json"}}],"schema_version":"1.7.5"}