CVE-2026-89990: ceph: lock mutex in ceph_mds_check_access()

Critical severity · published Sep 16, 2026

CVE-2026-89990

ceph: lock mutex in ceph_mds_check_access()

9.8

CVSS

0.6%

EPSS

On KEV

Description

In the Linux kernel, the following vulnerability has been resolved: ceph: lock mutex in ceph_mds_check_access() MDS session OPEN handling replaces mdsc->s_cap_auths under mdsc->mutex, freeing the previous array and its strings. ceph_mds_check_access() traverses this array without holding the mutex. A concurrent session reopen can therefore free the array while it is being inspected, resulting in a use-after-free like this: Unable to handle kernel paging request at virtual address 003aaad64b2c8bb9 [...] Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 56 UID: 2953037534 PID: 1253231 Comm: php-cgi8.4 Not tainted 6.18.45-i2-ampere #1146 NONE [..] pc : ceph_mds_check_access+0xd4/0x550 lr : ceph_mds_check_access+0xc8/0x550 [...] Call trace: ceph_mds_check_access+0xd4/0x550 (P) ceph_atomic_open+0x138/0xbe8 path_openat+0xa24/0xfa8 do_filp_open+0x94/0x158 do_sys_openat2+0x88/0xf8

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

None

Confidentiality

High

Integrity

High

Availability

High

Scope

Unchanged

Exploitation

Is it being used?

Exploit prediction (EPSS)0.6% · higher than 49% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

Linux · Linux

596afb0b8933ba6ed7227adcc538db26feb25c74 before 729c1ff670ece6f3d4b1738365a0b2f90d487523; 596afb0b8933ba6ed7227adcc538db26feb25c74 before ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3; 596afb0b8933ba6ed7227adcc538db26feb25c74 before df1a97d5313fccadb08390306d49b194fb027392; 596afb0b8933ba6ed7227adcc538db26feb25c74 before a61c6ae1dae2611082b831b4aaa780878099c012; 6.10 · source: vendor

Affected product

Linux

All Linux CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-89990

CVE.org

https://www.cve.org/CVERecord?id=CVE-2026-89990

git.kernel.org

https://git.kernel.org/stable/c/729c1ff670ece6f3d4b1738365a0b2f90d487523

git.kernel.org

https://git.kernel.org/stable/c/a61c6ae1dae2611082b831b4aaa780878099c012

git.kernel.org

https://git.kernel.org/stable/c/ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3

git.kernel.org

https://git.kernel.org/stable/c/df1a97d5313fccadb08390306d49b194fb027392