CVE-2026-89990

Summary

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

Affected Software

VendorProductVersion RangeStatus
LinuxLinux596afb0b8933ba6ed7227adcc538db26feb25c74 < 729c1ff670ece6f3d4b1738365a0b2f90d487523affected
LinuxLinux596afb0b8933ba6ed7227adcc538db26feb25c74 < ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3affected
LinuxLinux596afb0b8933ba6ed7227adcc538db26feb25c74 < df1a97d5313fccadb08390306d49b194fb027392affected
LinuxLinux596afb0b8933ba6ed7227adcc538db26feb25c74 < a61c6ae1dae2611082b831b4aaa780878099c012affected
LinuxLinux6.10affected
LinuxLinux0 < 6.10unaffected
LinuxLinux6.12.110 <= 6.12.*unaffected
LinuxLinux6.18.51 <= 6.18.*unaffected
LinuxLinux7.2.5 <= 7.2.*unaffected
LinuxLinux7.3-rc2 <= *unaffected

Weaknesses

References