{"id":"CVE-2026-89978","summary":"accel/amdxdna: return early from a zero-length flush","details":"In the Linux kernel, the following vulnerability has been resolved:\n\naccel/amdxdna: return early from a zero-length flush\n\nSYNC_BO does not constrain its size, so a request for zero bytes reaches\ndrm_clflush_virt_range(), which ends with an unconditional\nclflushopt(end - 1). For an empty range that is the byte before the\nmapping, and abo-\u003emem.kva comes from vmap(), so the access lands in the\nguard page below the vmalloc area and faults:\n\n  BUG: unable to handle page fault for address: ffffd16fbbc70fff\n  #PF: supervisor read access in kernel mode\n  Oops: Oops: 0000 [#1] SMP NOPTI\n  CPU: 7 UID: 1000 Comm: sync_bo_probe\n  RIP: 0010:drm_clflush_virt_range+0x3c/0x70\n  Call Trace:\n   amdxdna_drm_sync_bo_ioctl+0x124/0x430 [amdxdna]\n   drm_ioctl+0x301/0x4c0\n   __x64_sys_ioctl+0x115/0x2f0\n   do_syscall_64+0xa6/0x3d0\n\nAny process that can open the render node can do this. Reproduced 3 of 3\ntimes on a Strix Point NPU (1022:17f0), by calling SYNC_BO with size 0 on\nan AMDXDNA_BO_SHARE object. The import arm takes the same request but\nflushes the whole scatterlist, so it survives it.\n\nNothing needs flushing for an empty range, so answer before choosing a\npath.","modified":"2026-09-17T03:47:20.071995047Z","published":"2026-09-16T10:32:55.928Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89978.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/45962da5821d0a691f638ccb13842889156d8969"},{"type":"WEB","url":"https://git.kernel.org/stable/c/dc14753664240cedf669623b27ae9922b0618b25"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f00def884a831dc49eb659dac2dd09dbfd21e67f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89978.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89978"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"e252e3f3488a49267e08ea7d972ac5ba3f2f1763"},{"fixed":"45962da5821d0a691f638ccb13842889156d8969"},{"fixed":"f00def884a831dc49eb659dac2dd09dbfd21e67f"},{"fixed":"dc14753664240cedf669623b27ae9922b0618b25"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89978.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89978.json"}}],"schema_version":"1.9.0"}