{"id":"CVE-2026-97564","summary":"smb: client: reject userspace cifs.idmap descriptions","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: reject userspace cifs.idmap descriptions\n\ncifs.idmap key descriptions carry authority-bearing fields (owner and\ngroup SIDs and uid/gid values in \"os:\"/\"gs:\"/\"oi:\"/\"gi:\" form) that the\ncifs.idmap upcall helper treats as kernel-originating inputs.  Unlike\nits sibling cifs.spnego, the cifs.idmap key type has no vet_description\nhook, so userspace can create keys of this type through\nrequest_key(2)/add_key(2) and supply those fields without CIFS origin.\nA request_key(2) call with a non-NULL callout then drives a root\nusermodehelper upcall (/sbin/request-key -\u003e cifs.idmap) that consumes\nthe unvetted description in root context.\n\nOnly accept cifs.idmap descriptions while CIFS is using its private\nroot_cred to request the key.  id_to_sid()/sid_to_id() already run\nunder override_creds(root_cred), so the kernel-originated path is\nunaffected.\n\nThis mirrors commit 3da1fdf4efbc (\"smb: client: reject userspace\ncifs.spnego descriptions\"), which applied the same restriction to\ncifs.spnego.","modified":"2026-09-26T03:48:27.686339645Z","published":"2026-09-25T10:21:51.858Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97564.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/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97564.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97564"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4d79dba0e00749fa40de8ef13a9b85ce57a1603b"},{"fixed":"e5964064e3fbe6325893408faff08ca33de0e2c3"},{"fixed":"96751028c0d4dec785709ea3eb0ab38a4f2ded96"},{"fixed":"1d3b24b16a0b013792e8f1e3ed060f0b46f537d1"},{"fixed":"d9d7eeb0cea5b55b82888f443622fd8d4ee064f3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97564.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97564.json"}}],"schema_version":"1.9.0"}