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
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it