CVE-2025-22070fs/9p: fix NULL pointer dereference on mkdir
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In the Linux kernel, the following vulnerability has been resolved: fs/9p: fix NULL pointer dereference on mkdir When a 9p tree was mounted with option 'posixacl', parent directory had a default ACL set for its subdirectories, e.g.: setfacl -m default:group:simpsons:rwx parentdir then creating a subdirectory crashed 9p client, as v9fs_fid_add() call in function v9fs_vfs_mkdir_dotl() sets the passed 'fid' pointer to NULL (since dafbe689736) even though the subsequent v9fs_set_create_acl() call expects a valid non-NULL 'fid' pointer: [ 37.273191] BUG: kernel NULL pointer dereference, address: 0000000000000000 ... [ 37.322338] Call Trace: [ 37.323043] <TASK> [ 37.323621] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434) [ 37.324448] ? page_fault_oops (arch/x86/mm/fault.c:714) [ 37.325532] ? search_module_extables (kernel/module/main.c:3733) [ 37.326742] ? p9_client_walk (net/9p/client.c:1165) 9pnet [ 37.328006] ? search_bpf_extables (kernel/bpf/core.c:804) [ 37.329142] ? exc_page_fault (./arch/x86/include/asm/paravirt.h:686 arch/x86/mm/fault.c:1488 arch/x86/mm/fault.c:1538) [ 37.330196] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:574) [ 37.331330] ? p9_client_walk (net/9p/client.c:1165) 9pnet [ 37.332562] ? v9fs_fid_xattr_get (fs/9p/xattr.c:30) 9p [ 37.333824] v9fs_fid_xattr_set (fs/9p/fid.h:23 fs/9p/xattr.c:121) 9p [ 37.335077] v9fs_set_acl (fs/9p/acl.c:276) 9p [ 37.336112] v9fs_set_create_acl (fs/9p/acl.c:307) 9p [ 37.337326] v9fs_vfs_mkdir_dotl (fs/9p/vfs_inode_dotl.c:411) 9p [ 37.338590] vfs_mkdir (fs/namei.c:4313) [ 37.339535] do_mkdirat (fs/namei.c:4336) [ 37.340465] __x64_sys_mkdir (fs/namei.c:4354) [ 37.341455] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) [ 37.342447] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Fix this by simply swapping the sequence of these two calls in v9fs_vfs_mkdir_dotl(), i.e. calling v9fs_set_create_acl() before v9fs_fid_add().
- CVSS
- 5.5 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-476
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 21, 2026
- First seen by InfoSec Signals
- Oct 21, 2026
Affected products
Linux Linux linux:linux (from the name) | from dafbe689736f62c696ac64809b17bdc752cfbe76 before b17edabd917142d9ecd058f7c6ee9da5e32af1dd; from dafbe689736f62c696ac64809b17bdc752cfbe76 before 8522051c58d68146b93e8a5ba9987e83b3d64e7b; from dafbe689736f62c696ac64809b17bdc752cfbe76 before 2139dea5c53e3bb63ac49a6901c85e525a80ee8a; from dafbe689736f62c696ac64809b17bdc752cfbe76 before 6517b395cb1e43fbf3962dd93e6fb4a5e5ab100e; from dafbe689736f62c696ac64809b17bdc752cfbe76 before 3f61ac7c65bdb26accb52f9db66313597e759821 | CNA record |
linux linux_kernel linux:linux_kernel | from 6.0 before 6.12.23; from 6.13 before 6.13.11; from 6.14 before 6.14.2 | NVD |
References
- https://git.kernel.org/stable/c/b17edabd917142d9ecd058f7c6ee9da5e32af1dd
- https://git.kernel.org/stable/c/8522051c58d68146b93e8a5ba9987e83b3d64e7bpatch
- https://git.kernel.org/stable/c/2139dea5c53e3bb63ac49a6901c85e525a80ee8apatch
- https://git.kernel.org/stable/c/6517b395cb1e43fbf3962dd93e6fb4a5e5ab100epatch
- https://git.kernel.org/stable/c/3f61ac7c65bdb26accb52f9db66313597e759821patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.