{"id":"CVE-2025-39717","summary":"open_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nopen_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE\n\nAs described in commit 7a54947e727b ('Merge patch series \"fs: allow\nchanging idmappings\"'), open_tree_attr(2) was necessary in order to\nallow for a detached mount to be created and have its idmappings changed\nwithout the risk of any racing threads operating on it. For this reason,\nmount_setattr(2) still does not allow for id-mappings to be changed.\n\nHowever, there was a bug in commit 2462651ffa76 (\"fs: allow changing\nidmappings\") which allowed users to bypass this restriction by calling\nopen_tree_attr(2) *without* OPEN_TREE_CLONE.\n\ncan_idmap_mount() prevented this bug from allowing an attached\nmountpoint's id-mapping from being modified (thanks to an is_anon_ns()\ncheck), but this still allows for detached (but visible) mounts to have\ntheir be id-mapping changed. This risks the same UAF and locking issues\nas described in the merge commit, and was likely unintentional.","modified":"2026-08-12T03:51:43.011966139Z","published":"2025-09-05T17:21:24.528Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39717.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/69dbdc711d9130136824e3830191a6afffa0a1f0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9308366f062129d52e0ee3f7a019f7dd41db33df"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39717.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39717"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"2462651ffa76b87f9c2e4403ef6e6b89b703fb2f"},{"fixed":"69dbdc711d9130136824e3830191a6afffa0a1f0"},{"fixed":"9308366f062129d52e0ee3f7a019f7dd41db33df"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39717.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.15.0"},{"fixed":"6.16.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39717.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}