Security assessments indicate that CVE-2026-23189 presents a notable risk, potentially requiring prompt mitigation.
Status: Analyzed
Last updated: 🕔 18 Mar 2026, 17:18 UTC
Originally published on: 🕔 14 Feb 2026, 17:15 UTC
Time between publication and last update: 32 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVE-2026-23189: 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 ]
The exploitability of CVE-2026-23189 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2026-23189 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-23189, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-23189, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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