{"id":"CVE-2026-89489","summary":"openrisc: fix arbitrary kernel memory access via or1k_atomic syscall","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nopenrisc: fix arbitrary kernel memory access via or1k_atomic syscall\n\nsys_or1k_atomic() (syscall 244 in the \"or1k\" ABI) takes two user\npointers, v1 and v2, and swaps the words they point to in hand-written\nassembly.\n\n    l.lwz   r29,0(r4)\n    l.lwz   r27,0(r5)\n    l.sw    0(r4),r27\n    l.sw    0(r5),r29\n\nThe pointers are not checked with access_ok(). The four memory\naccesses also have no exception table entries.\n\nA caller passes a kernel address as either pointer, and the syscall\nreads from and writes to it directly.\n\nThis gives an unprivileged process a kernel read/write primitive. It\noverwrites kernel data such as the sys_call_table, gaining code\nexecution in kernel context.\n\nCheck both pointers before entering the critical section. Add fixups\nfor the four memory accesses so faults on valid but unmapped user\naddresses return -EFAULT.\n\n[shorne@gmail.com: fix comment style]","modified":"2026-09-13T03:47:18.413760263Z","published":"2026-09-11T19:43:42.164Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89489.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/78004e9a87f240df03e2f73120d291763c32e0a7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a520e8cac54fb403f3800125b606f55fcad42cb9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b53435c079c78f89f70a62dd5a322cca4e292b34"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d64a75369cd0f2ee79afcc9d9ca34a3890989379"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89489.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89489"},{"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":"9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a"},{"fixed":"a520e8cac54fb403f3800125b606f55fcad42cb9"},{"fixed":"d64a75369cd0f2ee79afcc9d9ca34a3890989379"},{"fixed":"b53435c079c78f89f70a62dd5a322cca4e292b34"},{"fixed":"78004e9a87f240df03e2f73120d291763c32e0a7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89489.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.1.0"},{"fixed":"6.12.109"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.50"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89489.json"}}],"schema_version":"1.9.0"}