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CVE Record

CVE-2024-44992: smb/client: avoid possible NULL dereference in cifs_free_subrequest()

In the Linux kernel, the following vulnerability has been resolved: smb/client: avoid possible NULL dereference in cifs_free_subrequest() Clang static checker (scan-build) warning: cifsglob.h:line 890, column 3 Access to field 'ops' results in a dereference of a null pointer. Commit 519be989717c ("cifs: Add a tracepoint to track credits involved in R/W requests") adds a check for 'rdata->server', and let clang throw this warning about NULL dereference. When 'rdata->credits.value != 0 && rdata->server == NULL' happens, add_credits_and_wake_if() will call rdata->server->ops->add_credits(). This will cause NULL dereference problem. Add a check for 'rdata->server' to avoid NULL dereference.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in the Linux kernel SMB/CIFS client can trigger a null-pointer dereference while releasing a request. The documented impact is a system crash or loss of availability, not data theft or modification. The supplied CVSS score is 7.5 (High).

Executive priority

Prioritize remediation on critical Linux systems using SMB/CIFS, especially where a crash would interrupt business services. This is a high-severity availability risk, but the supplied evidence does not show active exploitation, confidentiality loss, or integrity loss.

Technical view

In cifs_free_subrequest(), a request can retain nonzero credits while its server pointer is NULL. The credit-return path may then access server->ops->add_credits(), causing a NULL dereference. The kernel fix adds a server-pointer check. The supplied CVSS vector indicates network reachability, low complexity, no privileges or interaction, and availability-only impact.

Likely exposure

Exposure is limited to Linux systems running an affected kernel and exercising the SMB/CIFS client code. The bundle lists affected 6.10-series and 6.11 entries, but does not clearly express every boundary or distribution backport. Confirm the effective status with each Linux distributor.

Exploitation context

The supplied record does not establish active exploitation, and the CVE is not identified as CISA KEV. Although the CVSS vector describes network attack potential, the bundle provides no proof of a practical public exploit or reliable remote trigger. Treat exploitation status as unconfirmed.

Researcher notes

The issue was identified through Clang static analysis. The critical state is nonzero request credits combined with a NULL server pointer, followed by credit-return logic dereferencing server operations. Two upstream stable commit references are supplied. Exact reachability, trigger control, affected boundaries, and distribution-specific backports are not fully documented in the bundle.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable stable fix.
  • Check distributor guidance for backports and precise affected-version boundaries.
  • Prioritize SMB/CIFS-using systems where an availability failure would disrupt critical services.
  • Use vendor-recommended temporary mitigations if patching must be delayed.

Validation and detection

  • Inventory kernel versions on systems that use SMB/CIFS client functionality.
  • Confirm the installed vendor kernel includes the applicable stable fix or backport.
  • Review vendor advisories because package versions may not match upstream kernel numbering.
  • After updating, verify the intended kernel is running and SMB/CIFS workloads remain operational.
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-2024-44992 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

1CVSS vectors
3Timeline events
1ADP providers
3Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2024-44992Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux69c3c023af25edb5433a2db824d3e7cc328f0183, 69c3c023af25edb5433a2db824d3e7cc328f0183unaffected
LinuxLinux6.10, 0, 6.10.7, 6.11affected
Weakness

CWE details

No CWE listed

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