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CVE Record

CVE-2023-54076: smb: client: fix missed ses refcounting

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix missed ses refcounting Use new cifs_smb_ses_inc_refcount() helper to get an active reference of @ses and @ses->dfs_root_ses (if set). This will prevent @ses->dfs_root_ses of being put in the next call to cifs_put_smb_ses() and thus potentially causing an use-after-free bug.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2023-54076 is a Linux kernel SMB client memory-safety bug. The cited kernel fix says missed session reference counting could let a DFS root session be released too early, potentially causing a use-after-free. Business urgency depends on whether systems run affected kernels and use the SMB/CIFS client.

Executive priority

Handle through normal kernel vulnerability management, with higher priority for Linux assets that actively mount SMB/CIFS shares. Current sources do not justify emergency response, but the absence of CVSS and exploit data means exposure should be verified promptly.

Technical view

The issue is in Linux kernel SMB client session handling. The fix adds cifs_smb_ses_inc_refcount() to hold active references to ses and ses->dfs_root_ses before cifs_put_smb_ses(), preventing a possible use-after-free. The bundle provides no CVSS, CWE, exploitability details, or distro-specific backport matrix.

Likely exposure

Exposure appears limited to Linux systems running affected kernel builds that use the SMB/CIFS client, especially DFS-related session paths. The source bundle lists Linux as affected but version data is incomplete and should be mapped against vendor kernel packages.

Exploitation context

The bundle does not show CISA KEV listing or any cited active exploitation. It also does not establish attacker prerequisites, remote trigger conditions, or practical exploitability. Treat this as a kernel memory-safety issue requiring vendor-guided triage, not as confirmed in-the-wild exploitation.

Researcher notes

The primary evidence is the kernel fix description: missed reference counting around ses and dfs_root_ses could cause use-after-free after cifs_put_smb_ses(). The record lacks impact scoring, trigger details, and distribution status, so avoid broad claims beyond SMB client memory safety.

Mitigation direction

  • Apply Linux stable or distribution kernel updates containing the referenced fix commits.
  • Check vendor advisories for backported fixes matching your exact kernel package.
  • Prioritize systems that mount SMB/CIFS shares or use DFS paths.
  • If patching is delayed, reduce unnecessary SMB/CIFS client usage where feasible.

Validation and detection

  • Inventory running Linux kernel versions across servers, endpoints, and appliances.
  • Identify hosts using the kernel SMB/CIFS client or DFS mounts.
  • Compare vendor package changelogs against CVE-2023-54076 and referenced stable commits.
  • Confirm patched kernels are deployed and systems have rebooted into them.
Prepared
Confidence
medium
Sources
4

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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2023-54076 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
3Source 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
LinuxLinux8e3554150d6c80a84b3cb046615d1a0e943811dc, 8e3554150d6c80a84b3cb046615d1a0e943811dc, f30d226bcc9f0e2d97b4a6e94c43a28148fbeab6, c082c3be0f96e759ff2e361d929832fda0b93851, 6.2.15, 6.3.2unaffected
LinuxLinux6.4, 0, 6.4.7, 6.5affected
Weakness

CWE details

No CWE listed

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