{"id":"CVE-2026-97564","title":"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:…","summary":"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:…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < e5964064e3fbe6325893408faff08ca33de0e2c3","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < 96751028c0d4dec785709ea3eb0ab38a4f2ded96","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < d9d7eeb0cea5b55b82888f443622fd8d4ee064f3","Linux 3.0"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T11:17:07.007","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97564","references":[{"url":"https://git.kernel.org/stable/c/1d3b24b16a0b013792e8f1e3ed060f0b46f537d1","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/96751028c0d4dec785709ea3eb0ab38a4f2ded96","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d9d7eeb0cea5b55b82888f443622fd8d4ee064f3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e5964064e3fbe6325893408faff08ca33de0e2c3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.914Z","slug":"CVE-2026-97564","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}