UBUNTU-CVE-2026-23205
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
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
50 explicit affected versions
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6 explicit affected versions
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38 explicit affected versions
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37 explicit affected versions
11 explicit affected versions
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37 explicit affected versions
3 explicit affected versions
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38 explicit affected versions
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5 explicit affected versions
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33 explicit affected versions
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11 explicit affected versions
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3 explicit affected versions
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16 explicit affected versions
18 explicit affected versions
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5 explicit affected versions
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10 explicit affected versions
7 explicit affected versions
43 explicit affected versions
13 explicit affected versions
13 explicit affected versions
7 explicit affected versions
8 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
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14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
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11 explicit affected versions
36 explicit affected versions
17 explicit affected versions
14 explicit affected versions
8 explicit affected versions
7 explicit affected versions
4 explicit affected versions
10 explicit affected versions
1 explicit affected versions
13 explicit affected versions
43 explicit affected versions
16 explicit affected versions
10 explicit affected versions
8 explicit affected versions
42 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
14 explicit affected versions
11 explicit affected versions
1 explicit affected versions
16 explicit affected versions
37 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/e3a43633023e3cacaca60d4b8972d084a2b06236
- https://git.kernel.org/stable/c/3a6d6b332f92990958602c1e35ce0173e2dd62e9
- https://git.kernel.org/stable/c/743f70406264348c0830f38409eb6c40a42fb2db
- https://git.kernel.org/stable/c/9ee608a64e37cea5b4b13e436c559dd0fb2ad1b5
- https://git.kernel.org/stable/c/b64e3b5d8d759dd4333992e4ba4dadf9359952c8
- https://git.kernel.org/stable/c/e3a43633023e3cacaca60d4b8972d084a2b06236
- https://ubuntu.com/security/CVE-2026-23205
- https://ubuntu.com/security/notices/USN-8278-1
- https://ubuntu.com/security/notices/USN-8278-2
- https://ubuntu.com/security/notices/USN-8289-1
- https://ubuntu.com/security/notices/USN-8289-2
- https://ubuntu.com/security/notices/USN-8296-1
- https://ubuntu.com/security/notices/USN-8296-2
- https://ubuntu.com/security/notices/USN-8393-1
- https://ubuntu.com/security/notices/USN-8440-1
- https://ubuntu.com/security/notices/USN-8499-1
- https://www.cve.org/CVERecord?id=CVE-2026-23205