{"id":"CVE-2026-98173","summary":"smb: client: fix use-after-free of iface in cifs_try_adding_channels()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-after-free of iface in cifs_try_adding_channels()\n\ncifs_try_adding_channels() iterates ses-\u003eiface_list with\nlist_for_each_entry_safe_from(), which captures the next entry\n(niface) under iface_lock.  The loop body then drops iface_lock for\nthe whole duration of cifs_ses_add_channel().\n\nA concurrent interface refresh (SMB3_request_interfaces() -\u003e\nparse_server_interfaces()) marks all ifaces inactive and removes and\nfrees any that are not re-advertised via list_del() + kref_put(),\nwhere release_iface() is a bare kfree().  Since niface typically has\nno channel holding a reference, the list reference is its last and it\ncan be freed inside the unlocked window.  On continue, the iterator\nadvance step then dereferences niface-\u003eiface_head.next, and the loop\nbody reads iface-\u003erdma_capable/is_active, both on freed memory.\n\nFix this by never keeping an unreferenced list pointer across the\nunlocked window.  Each channel attempt now re-scans the list from the\nhead under iface_lock, takes a kref on the selected candidate, and\npasses only that referenced candidate to cifs_ses_add_channel().\nweight_fulfilled still tracks selection progress, so restarting the\nscan preserves the original weighted distribution and the\nweight_fulfilled-before-kref_put ordering on the failure path.\n\nAdd a per-pass attempts cap so a flapping interface refresh cannot\nkeep the inner loop spinning within a single tries increment.","modified":"2026-10-07T02:47:29.319348012Z","published":"2026-10-06T08:44:17.567Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98173.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/c941f1ebfd26f683de81091473f3596a218abff0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d034e836eefd7ce75e588f7031cffbeec594f5ac"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e99040e5e9c60441e6b4725e1a7b88c3106ae903"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ec36b38e65596950e6c29bed7dfc90b98707c19c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98173.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98173"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"aa45dadd34e44fcd6a9df4b395bee5b5633b4cec"},{"fixed":"c941f1ebfd26f683de81091473f3596a218abff0"},{"fixed":"e99040e5e9c60441e6b4725e1a7b88c3106ae903"},{"fixed":"ec36b38e65596950e6c29bed7dfc90b98707c19c"},{"fixed":"d034e836eefd7ce75e588f7031cffbeec594f5ac"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98173.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.19.0"},{"fixed":"6.12.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.54"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98173.json"}}],"schema_version":"1.9.0"}