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CVE Record

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

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

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2026-23205 is a Linux kernel SMB/CIFS client memory leak. The documented issue occurs when opening a file over an SMB mount fails, leaving request-buffer objects allocated. It appears most relevant to Linux clients that mount SMB shares, not SMB servers. No source provided shows active exploitation or business impact beyond resource leakage.

Executive priority

Handle through normal kernel patch management unless SMB-mounted Linux clients are critical or memory constrained. There is not enough evidence to justify emergency action, but unresolved kernel memory leaks can affect availability over time.

Technical view

The kernel fix is titled “smb/client: fix memory leak in smb2_open_file().” The source describes remaining cifs_small_rq slab objects during CIFS module cleanup after failed direct write activity against a read-only SMB export. Severity, CVSS, and CWE are not provided in the bundle.

Likely exposure

Exposure is likely limited to Linux systems using the CIFS/SMB client module to mount SMB shares. Systems that do not load or use the cifs client path are unlikely to be exposed based on the provided evidence.

Exploitation context

The bundle provides a reproducer for the leak but no evidence of remote code execution, privilege escalation, public exploitation, or CISA KEV listing. Treat exploitation status as unknown, with no confirmed active exploitation in the provided sources.

Researcher notes

The source bundle identifies a memory leak in smb2_open_file() and references stable kernel commits. It does not provide CVSS, CWE, exploit maturity, or distribution-specific package status. Validate exposure through kernel version, backport status, and actual CIFS client usage.

Mitigation direction

  • Check vendor kernel advisories for fixed packages or backports.
  • Prioritize updates for Linux clients that actively mount SMB shares.
  • Avoid unnecessary CIFS module use on systems that do not need SMB mounts.
  • Monitor hosts using CIFS for abnormal memory pressure until patched.

Validation and detection

  • Inventory Linux hosts with CIFS/SMB client mounts or loaded cifs modules.
  • Compare running kernel versions against vendor-fixed kernel packages.
  • Review kernel logs for cifs_small_rq slab cleanup warnings.
  • Confirm affected systems receive a kernel containing the referenced stable fixes.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-23205 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux17e53a15e64b65623b8f2b1185d27d7b1cbf69ab, 18066188eb90cc0c798f3370a8078a79ddb73f70, 6ebb9d54eccc8026b386e76eff69364d33373da5, e255612b5ed9f179abe8196df7c2ba09dd227900, e255612b5ed9f179abe8196df7c2ba09dd227900, bcd15f06c7e8904116cfb06526bcc189b86aff85, 6.1.141, 6.6.93, 6.12.31, 6.14.9unaffected
LinuxLinux6.15, 0, 6.1.163, 6.6.124, 6.12.70, 6.18.10, 6.19affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.