CVE-2026-89990 in Linux
Riassunto
di MITRE • 16/09/2026
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
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