CVE-2026-23189
Unknown
Unknown - Not Provided
NULL Pointer Dereference in Linux Kernel CephFS Client
Publication date: 2026-02-14
Last updated on: 2026-03-18
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
ceph: fix NULL pointer dereference in ceph_mds_auth_match()
The CephFS kernel client has regression starting from 6.18-rc1.
We have issue in ceph_mds_auth_match() if fs_name == NULL:
const char fs_name = mdsc->fsc->mount_options->mds_namespace;
...
if (auth->match.fs_name && strcmp(auth->match.fs_name, fs_name)) {
/ fsname mismatch, try next one */
return 0;
}
Patrick Donnelly suggested that: In summary, we should definitely start
decoding `fs_name` from the MDSMap and do strict authorizations checks
against it. Note that the `-o mds_namespace=foo` should only be used for
selecting the file system to mount and nothing else. It's possible
no mds_namespace is specified but the kernel will mount the only
file system that exists which may have name "foo".
This patch reworks ceph_mdsmap_decode() and namespace_equals() with
the goal of supporting the suggested concept. Now struct ceph_mdsmap
contains m_fs_name field that receives copy of extracted FS name
by ceph_extract_encoded_string(). For the case of "old" CephFS file
systems, it is used "cephfs" name.
[ idryomov: replace redundant %*pE with %s in ceph_mdsmap_decode(),
get rid of a series of strlen() calls in ceph_namespace_match(),
drop changes to namespace_equals() body to avoid treating empty
mds_namespace as equal, drop changes to ceph_mdsc_handle_fsmap()
as namespace_equals() isn't an equivalent substitution there ]
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | From 6.12.58 (inc) to 6.12.70 (exc) |
| linux | linux_kernel | From 6.17.8 (inc) to 6.18.10 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-476 | The product dereferences a pointer that it expects to be valid but is NULL. |
