smb/client: fix memory leak in smb2_open_file() (CVE-2026-23205)

Summary

smb/client: fix memory leak in smb2_open_file()

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved:

smb/client: fix memory leak in smb2_open_file()

Reproducer:

server: directories are exported read-only
client: mount -t cifs //${server_ip}/export /mnt
client: dd if=/dev/zero of=/mnt/file bs=512 count=1000 oflag=direct
client: umount /mnt
client: sleep 1
client: modprobe -r cifs

The error message is as follows:

=============================================================================
BUG cifs_small_rq (Not tainted): Objects remaining on __kmem_cache_shutdown()

Object 0x00000000d47521be @offset=14336
...
WARNING: mm/slub.c:1251 at __kmem_cache_shutdown+0x34e/0x440, CPU#0: modprobe/1577
...
Call Trace:

kmem_cache_destroy+0x94/0x190
cifs_destroy_request_bufs+0x3e/0x50 [cifs]
cleanup_module+0x4e/0x540 [cifs]
__se_sys_delete_module+0x278/0x400
__x64_sys_delete_module+0x5f/0x70
x64_sys_call+0x2299/0x2ff0
do_syscall_64+0x89/0x350
entry_SYSCALL_64_after_hwframe+0x76/0x7e
...
kmem_cache_destroy cifs_small_rq: Slab cache still has objects when called from cifs_destroy_request_bufs+0x3e/0x50 [cifs]
WARNING: mm/slab_common.c:532 at kmem_cache_destroy+0x16b/0x190, CPU#0: modprobe/1577

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.163"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.124"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.70"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.10"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-23205 linux-lts Fixed in: 6.1.163-r0
Debian DEBIAN-CVE-2026-23205 linux Fixed in: 6.1.164-1
Ubuntu UBUNTU-CVE-2026-23205 linux-hwe-edge