CVE-2026-23189
Last modified
CVE-2026-23189 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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. EPSS estimates a 0.11% chance of exploitation in the next 30 days.
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 ]
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Linux | Linux Kernel | >= 6.12.58, < 6.12.70 | — |
| Linux | Linux Kernel | >= 6.17.8, < 6.18.10 | — |
| Linux | Linux Kernel | 6.19 | Rc1 |
References
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-23189?
How severe is CVE-2026-23189?
How do I fix CVE-2026-23189?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-23183In the Linux kernel, the following vulnerability has been re…
- CVE-2026-23184In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2026-23185In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2026-23186In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2026-23187In the Linux kernel, the following vulnerability has been re…7.1
- CVE-2026-23188In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2026-2319Race in DevTools in Google Chrome prior to 145.0.7632.45 all…7.5
- CVE-2026-23190In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2026-23191In the Linux kernel, the following vulnerability has been re…7
- CVE-2026-23192In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2026-23193In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2026-23194In the Linux kernel, the following vulnerability has been re…7.8
Are you affected by CVE-2026-23189?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST
