{"id":"CVE-2026-97564","published":"2026-09-25T11:17:07.007","lastModified":"2026-09-25T11:17:07.007","description":"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 -> 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.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1","tags":[]},{"url":"https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96","tags":[]},{"url":"https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3","tags":[]},{"url":"https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}