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

What is CVE-2026-23205?

CVE-2026-23205 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

smb/client: fix memory leak in smb2_open_file()

Reproducer:

1. server: directories are exported read-only 2. client: mount -t cifs //${server_ip}/export /mnt 3. client: dd if=/dev/zero of=/mnt/file bs=512 count=1000 oflag=direct 4. client: umount /mnt 5. client: sleep 1 6. 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: <TASK> 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

Weakness: CWE-401

Which versions are affected by CVE-2026-23205?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-23205?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-23205 being exploited?

There is no known exploitation of CVE-2026-23205 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-23205, DEBIAN-CVE-2026-23205, GHSA-9rcv-5g2j-597r, ROOT-OS-DEBIAN-12-CVE-2026-23205, ROOT-OS-DEBIAN-13-CVE-2026-23205, ROOT-OS-UBUNTU-2404-CVE-2026-23205 and 1 more.