{"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":"high","cvss":7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-346"],"vendor":"Linux","product":"Linux","affected":["Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < 17c93bcd17755523c21abb22cbf2a41a6eb0caaf","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < e5964064e3fbe6325893408faff08ca33de0e2c3","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < 96751028c0d4dec785709ea3eb0ab38a4f2ded96","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < 1d3b24b16a0b013792e8f1e3ed060f0b46f537d1","Linux >= 4d79dba0e00749fa40de8ef13a9b85ce57a1603b < d9d7eeb0cea5b55b82888f443622fd8d4ee064f3","Linux 3.0"],"published":"2026-09-25","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:18:03.980","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97564","references":[{"url":"https://git.kernel.org/stable/c/17c93bcd17755523c21abb22cbf2a41a6eb0caaf","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"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"},{"url":"https://git.kernel.org/stable/c/f29c1ec0e7d8c887a91df3f93bb4617c0ac95c6a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97564.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-97564"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541148"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-97564"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97564"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97564.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00211,"epssPercentile":0.11321,"cvssSource":"vendor","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.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-09-29 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97564.json)","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":38.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":212337,"id":"CVE-2026-97564","ts":1790668153366,"field":"cvss","old":null,"new":"7"},{"seq":212336,"id":"CVE-2026-97564","ts":1790668153366,"field":"severity","old":"none","new":"high"}]}