{"id":"CVE-2025-22070","title":"fs/9p: fix NULL pointer dereference on mkdir","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/9p: fix NULL pointer dereference on mkdir\n\nWhen a 9p tree was mounted with option 'posixacl', parent directory had a\ndefault ACL set for its subdirectories, e.g.:\n\n …","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"adp","vendor":"Linux","product":"Linux","affected":["Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < b17edabd917142d9ecd058f7c6ee9da5e32af1dd","Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 8522051c58d68146b93e8a5ba9987e83b3d64e7b","Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 2139dea5c53e3bb63ac49a6901c85e525a80ee8a","Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 6517b395cb1e43fbf3962dd93e6fb4a5e5ab100e","Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 3f61ac7c65bdb26accb52f9db66313597e759821","Linux 6.0"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2025-10-01T16:15:56.459715Z"},"published":"2025-04-16","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:36:13.739Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-22070","references":[{"url":"https://git.kernel.org/stable/c/b17edabd917142d9ecd058f7c6ee9da5e32af1dd"},{"url":"https://git.kernel.org/stable/c/8522051c58d68146b93e8a5ba9987e83b3d64e7b"},{"url":"https://git.kernel.org/stable/c/2139dea5c53e3bb63ac49a6901c85e525a80ee8a"},{"url":"https://git.kernel.org/stable/c/6517b395cb1e43fbf3962dd93e6fb4a5e5ab100e"},{"url":"https://git.kernel.org/stable/c/3f61ac7c65bdb26accb52f9db66313597e759821"}],"tags":["cve.org"],"epss":0.00239,"epssPercentile":0.14906,"ingestedAt":"2026-10-21T12:48:53.714Z","slug":"CVE-2025-22070","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nfs/9p: fix NULL pointer dereference on mkdir\n\nWhen a 9p tree was mounted with option 'posixacl', parent directory had a\ndefault ACL set for its subdirectories, e.g.:\n\n  setfacl -m default:group:simpsons:rwx parentdir\n\nthen creating a subdirectory crashed 9p client, as v9fs_fid_add() call in\nfunction v9fs_vfs_mkdir_dotl() sets the passed 'fid' pointer to NULL\n(since dafbe689736) even though the subsequent v9fs_set_create_acl() call\nexpects a valid non-NULL 'fid' pointer:\n\n  [   37.273191] BUG: kernel NULL pointer dereference, address: 0000000000000000\n  ...\n  [   37.322338] Call Trace:\n  [   37.323043]  <TASK>\n  [   37.323621] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434)\n  [   37.324448] ? page_fault_oops (arch/x86/mm/fault.c:714)\n  [   37.325532] ? search_module_extables (kernel/module/main.c:3733)\n  [   37.326742] ? p9_client_walk (net/9p/client.c:1165) 9pnet\n  [   37.328006] ? search_bpf_extables (kernel/bpf/core.c:804)\n  [   37.329142] ? exc_page_fault (./arch/x86/include/asm/paravirt.h:686 arch/x86/mm/fault.c:1488 arch/x86/mm/fault.c:1538)\n  [   37.330196] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:574)\n  [   37.331330] ? p9_client_walk (net/9p/client.c:1165) 9pnet\n  [   37.332562] ? v9fs_fid_xattr_get (fs/9p/xattr.c:30) 9p\n  [   37.333824] v9fs_fid_xattr_set (fs/9p/fid.h:23 fs/9p/xattr.c:121) 9p\n  [   37.335077] v9fs_set_acl (fs/9p/acl.c:276) 9p\n  [   37.336112] v9fs_set_create_acl (fs/9p/acl.c:307) 9p\n  [   37.337326] v9fs_vfs_mkdir_dotl (fs/9p/vfs_inode_dotl.c:411) 9p\n  [   37.338590] vfs_mkdir (fs/namei.c:4313)\n  [   37.339535] do_mkdirat (fs/namei.c:4336)\n  [   37.340465] __x64_sys_mkdir (fs/namei.c:4354)\n  [   37.341455] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83)\n  [   37.342447] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n\nFix this by simply swapping the sequence of these two calls in\nv9fs_vfs_mkdir_dotl(), i.e. calling v9fs_set_create_acl() before\nv9fs_fid_add().\n\n## Affected\n\n- `Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < b17edabd917142d9ecd058f7c6ee9da5e32af1dd`\n- `Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 8522051c58d68146b93e8a5ba9987e83b3d64e7b`\n- `Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 2139dea5c53e3bb63ac49a6901c85e525a80ee8a`\n- `Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 6517b395cb1e43fbf3962dd93e6fb4a5e5ab100e`\n- `Linux >= dafbe689736f62c696ac64809b17bdc752cfbe76 < 3f61ac7c65bdb26accb52f9db66313597e759821`\n- `Linux 6.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}