CVE-2025-40072— fanotify: Validate the return value of mnt_ns_from_dentry() before dereferencing
Quick assessment
Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未验证mnt_ns_from_dentry返回值，可能导致空指针取消引用。
Affected Version Matrix 6
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | 58f5fbeb367ff6f30a2448b2cad70f70b2de4b06< 73ce2a774ad6497cbd48dc4f8a5d699bc417f3fa |
affected |
58f5fbeb367ff6f30a2448b2cad70f70b2de4b06< 62e59ffe8787b5550ccff70c30b6f6be6a3ac3dd |
affected | ||
6.16 |
affected | ||
< 6.16 |
unaffected | ||
6.17.3≤ 6.17.* |
unaffected | ||
6.18≤ * |
unaffected |
Get alerts for future matching vulnerabilities
Log in to subscribe
I. Basic Information for CVE-2025-40072
Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗
Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.
Vulnerability Title
fanotify: Validate the return value of mnt_ns_from_dentry() before dereferencing
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
fanotify: Validate the return value of mnt_ns_from_dentry() before dereferencing
The function do_fanotify_mark() does not validate if
mnt_ns_from_dentry() returns NULL before dereferencing mntns->user_ns.
This causes a NULL pointer dereference in do_fanotify_mark() if the
path is not a mount namespace object.
Fix this by checking mnt_ns_from_dentry()'s return value before
dereferencing it.
Before the patch
$ gcc fanotify_nullptr.c -o fanotify_nullptr
$ mkdir A
$ ./fanotify_nullptr
Fanotify fd: 3
fanotify_mark: Operation not permitted
$ unshare -Urm
Fanotify fd: 3
Killed
int main(void){
int ffd;
ffd = fanotify_init(FAN_CLASS_NOTIF | FAN_REPORT_MNT, 0);
if(ffd < 0){
perror("fanotify_init");
exit(EXIT_FAILURE);
}
printf("Fanotify fd: %d\n",ffd);
if(fanotify_mark(ffd, FAN_MARK_ADD | FAN_MARK_MNTNS,
FAN_MNT_ATTACH, AT_FDCWD, "A") < 0){
perror("fanotify_mark");
exit(EXIT_FAILURE);
}
return 0;
}
After the patch
$ gcc fanotify_nullptr.c -o fanotify_nullptr
$ mkdir A
$ ./fanotify_nullptr
Fanotify fd: 3
fanotify_mark: Operation not permitted
$ unshare -Urm
Fanotify fd: 3
fanotify_mark: Invalid argument
[ 25.694973] BUG: kernel NULL pointer dereference, address: 0000000000000038
[ 25.695006] #PF: supervisor read access in kernel mode
[ 25.695012] #PF: error_code(0x0000) - not-present page
[ 25.695017] PGD 109a30067 P4D 109a30067 PUD 142b46067 PMD 0
[ 25.695025] Oops: Oops: 0000 [#1] SMP NOPTI
[ 25.695032] CPU: 4 UID: 1000 PID: 1478 Comm: fanotify_nullpt Not
tainted 6.17.0-rc4 #1 PREEMPT(lazy)
[ 25.695040] Hardware name: VMware, Inc. VMware Virtual
Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
[ 25.695049] RIP: 0010:do_fanotify_mark+0x817/0x950
[ 25.695066] Code: 04 00 00 e9 45 fd ff ff 48 8b 7c 24 48 4c 89 54
24 18 4c 89 5c 24 10 4c 89 0c 24 e8 b3 11 fc ff 4c 8b 54 24 18 4c 8b
5c 24 10 <48> 8b 78 38 4c 8b 0c 24 49 89 c4 e9 13 fd ff ff 8b 4c 24 28
85 c9
[ 25.695081] RSP: 0018:ffffd31c469e3c08 EFLAGS: 00010203
[ 25.695104] RAX: 0000000000000000 RBX: 0000000001000000 RCX: ffff8eb48aebd220
[ 25.695110] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8eb4835e8180
[ 25.695115] RBP: 0000000000000111 R08: 0000000000000000 R09: 0000000000000000
[ 25.695142] R10: ffff8eb48a7d56c0 R11: ffff8eb482bede00 R12: 00000000004012a7
[ 25.695148] R13: 0000000000000110 R14: 0000000000000001 R15: ffff8eb48a7d56c0
[ 25.695154] FS: 00007f8733bda740(0000) GS:ffff8eb61ce5f000(0000)
knlGS:0000000000000000
[ 25.695162] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 25.695170] CR2: 0000000000000038 CR3: 0000000136994006 CR4: 00000000003706f0
[ 25.695201] Call Trace:
[ 25.695209] <TASK>
[ 25.695215] __x64_sys_fanotify_mark+0x1f/0x30
[ 25.695222] do_syscall_64+0x82/0x2c0
...
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未验证mnt_ns_from_dentry返回值，可能导致空指针取消引用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2025-40072
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
Premium
No public POC found.
Login to generate AI POCIII. Intelligence Information for CVE-2025-40072
请登录查看更多情报信息。
Same Patch Batch · Linux · 2025-10-28 · 58 CVEs total
| CVE-2025-40074 | 9.8 CRITICAL | ipv4: start using dst_dev_rcu() |
| CVE-2025-40043 | 8.8 HIGH | net: nfc: nci: Add parameter validation for packet data |
| CVE-2025-40039 | 8.8 HIGH | ksmbd: Fix race condition in RPC handle list access |
| CVE-2025-40058 | 8.8 HIGH | iommu/vt-d: Disallow dirty tracking if incoherent page walk |
| CVE-2025-40046 | 8.6 HIGH | io_uring/zcrx: fix overshooting recv limit |
| CVE-2025-40068 | 8.4 HIGH | fs: ntfs3: Fix integer overflow in run_unpack() |
| CVE-2025-40075 | 8.1 HIGH | tcp_metrics: use dst_dev_net_rcu() |
| CVE-2025-40026 | 7.9 HIGH | KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O |
| CVE-2025-40027 | 7.8 HIGH | net/9p: fix double req put in p9_fd_cancelled |
| CVE-2025-40051 | 7.8 HIGH | vhost: vringh: Modify the return value check |
| CVE-2025-40061 | 7.8 HIGH | RDMA/rxe: Fix race in do_task() when draining |
| CVE-2025-40081 | 7.8 HIGH | perf: arm_spe: Prevent overflow in PERF_IDX2OFF() |
| CVE-2025-40079 | 7.8 HIGH | riscv, bpf: Sign extend struct ops return values properly |
| CVE-2025-40028 | 7.8 HIGH | binder: fix double-free in dbitmap |
| CVE-2025-40041 | 7.8 HIGH | LoongArch: BPF: Sign-extend struct ops return values properly |
| CVE-2025-40054 | 7.8 HIGH | f2fs: fix UAF issue in f2fs_merge_page_bio() |
| CVE-2025-40044 | 7.8 HIGH | fs: udf: fix OOB read in lengthAllocDescs handling |
| CVE-2025-40045 | 7.8 HIGH | ASoC: codecs: wcd937x: set the comp soundwire port correctly |
| CVE-2025-40025 | 7.8 HIGH | f2fs: fix to do sanity check on node footer for non inode dnode |
| CVE-2025-40047 | 7.8 HIGH | io_uring/waitid: always prune wait queue entry in io_waitid_wait() |
Showing top 20 of 58 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Linux
-
CVE-2023-7356
Bluetooth: ISO: Copy BASE if service data matches EIR_BAA_SE -
CVE-2026-98869
bpf: Infer zext_dst based on static register liveness analys -
CVE-2026-98868
dm-pcache: reject a kset that overruns its segment -
CVE-2026-98867
dm-pcache: bound the logical key offset from persistent memo -
CVE-2026-98866
sched/cache: Introduce task_struct->sched_cache_grp to fix U
Same vendor: Linux
-
CVE-2023-7356
Bluetooth: ISO: Copy BASE if service data matches EIR_BAA_SE -
CVE-2026-98869
bpf: Infer zext_dst based on static register liveness analys -
CVE-2026-98868
dm-pcache: reject a kset that overruns its segment -
CVE-2026-98867
dm-pcache: bound the logical key offset from persistent memo -
CVE-2026-98866
sched/cache: Introduce task_struct->sched_cache_grp to fix U
V. Comments for CVE-2025-40072
No comments yet