CVE-2025-40362: Linux kernel · ceph: fix multifs mds auth caps issue
Source GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
The vulnerability description references a resolved fix in the Linux kernel Ceph component, indicating that an official fix exists. Users should monitor the official Linux kernel and Ceph project advisories for patches addressing CVE-2025-40362 and apply them promptly once available. Until patched, restrict access to Ceph clusters and carefully manage user permissions to minimize risk.
Description
A vulnerability in the Linux kernel's Ceph filesystem component allowed improper validation of multi-filesystem (multifs) MDS authorization capabilities. Specifically, the MDS auth caps check did not validate the filesystem name (fsname) along with the associated capabilities, causing the authorization caps of one filesystem to be incorrectly applied to another. This flaw permitted users to gain elevated permissions on filesystems where they should have had restricted access, such as performing write operations on a read-only filesystem. The issue has been resolved by adding proper fsname validation in the authorization checks.
References
- nvd.nist.gov/vuln/detail/CVE-2025-40362 (opens in a new tab)
- git.kernel.org/stable/c/07640d34a781bb2e39020a39137073c03c4aa932 (opens in a new tab)
- git.kernel.org/stable/c/22c73d52a6d05c5a2053385c0d6cd9984732799d (opens in a new tab)
- git.kernel.org/stable/c/ca3da8b27ab9a0923ad477447cfb8fc7f4b4c523 (opens in a new tab)