{"id":"CVE-2026-68455","summary":"liveupdate: validate session type before performing operation","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nliveupdate: validate session type before performing operation\n\nThe sessions ioctls are not applicable to all session types. PRESERVE_FD\nis only applicable to outgoing sessions. RETRIEVE_FD and FINISH are only\nvalid for incoming session. Calling a incoming ioctl on an outgoing\nsession is invalid and can cause file handlers to run into unexpected\nerrors.\n\nFor example, a user can create a (outgoing) session, preserve a memfd,\nand then immediately do a retrieve without doing a kexec in between.\nThis would result in memfd's retrieve handler to run. The handlers\nexpects to be called from a post-kexec context, and will try to do a\nkho_restore_vmalloc() or kho_restore_folio() to try and restore memory.\n\nKHO catches this (thanks to KHO_PAGE_MAGIC) and returns an error, but\nsince this is considered an internal error and KHO throws out a bunch of\nWARN()s.\n\nAssociate a type with each ioctl op and validate the type in\nluo_session_ioctl() before dispatching the ioctl handler to make sure\nthe op is being called for the right session type.","modified":"2026-08-18T03:31:01.528589371Z","published":"2026-08-15T05:51:16.745Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68455.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3dc8a46d08a8a060d4128e9f497060b8d03c1595"},{"type":"WEB","url":"https://git.kernel.org/stable/c/507e3b479f9c6d85135eb5e1a77fb3fddb259ad8"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68455.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68455"},{"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":"16cec0d265219f14a7fcebcc43aeb69205adba56"},{"fixed":"3dc8a46d08a8a060d4128e9f497060b8d03c1595"},{"fixed":"507e3b479f9c6d85135eb5e1a77fb3fddb259ad8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68455.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68455.json"}}],"schema_version":"1.9.0"}