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CVE Record

CVE-2024-47809: dlm: fix possible lkb_resource null dereference

In the Linux kernel, the following vulnerability has been resolved: dlm: fix possible lkb_resource null dereference This patch fixes a possible null pointer dereference when this function is called from request_lock() as lkb->lkb_resource is not assigned yet, only after validate_lock_args() by calling attach_lkb(). Another issue is that a resource name could be a non printable bytearray and we cannot assume to be ASCII coded. The log functionality is probably never being hit when DLM is used in normal way and no debug logging is enabled. The null pointer dereference can only occur on a new created lkb that does not have the resource assigned yet, it probably never hits the null pointer dereference but we should be sure that other changes might not change this behaviour and we actually can hit the mentioned null pointer dereference. In this patch we just drop the printout of the resource name, the lkb id is enough to make a possible connection to a resource name if this exists.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's Takemoderate

Analyst readout for executives and security teams

Plain-English summary

CVE-2024-47809 is a Linux kernel availability issue in DLM. A local authenticated user could potentially trigger a kernel null pointer dereference, causing a crash or denial of service. The sources describe this as unlikely in normal DLM use and mostly tied to logging/debug behavior.

Executive priority

Treat this as a moderate patching item, not an emergency. The impact is service availability, and exploitation requires local access. Prioritize production Linux clusters or systems using DLM, then include the fix in normal kernel maintenance cycles.

Technical view

The flaw is a CWE-476 null pointer dereference in Linux DLM. During request_lock(), lkb_resource may not yet be assigned before validate_lock_args() and attach_lkb(). Logging attempted to reference resource-name data that may be unavailable or non-printable. The fix removes resource-name output from that path.

Likely exposure

Exposure is limited to Linux systems running affected kernels where DLM code is present and reachable by a local privileged or authenticated context. The CVSS vector is local, low complexity, low privileges, no user interaction, and high availability impact only.

Exploitation context

The source bundle does not show KEV listing or active exploitation. The kernel description says the problematic logging path is probably never hit during normal DLM use without debug logging, but it was fixed defensively to prevent future reachable crashes.

Researcher notes

Evidence supports a local denial-of-service risk in DLM only. The source text stresses uncertain reachability under normal use and no named exploitation. Do not broaden scope beyond Linux kernel DLM without vendor evidence.

Mitigation direction

  • Update affected Linux kernels through vendor-supported security packages.
  • Confirm the applied kernel includes one of the referenced stable fixes.
  • If immediate patching is delayed, review vendor guidance for DLM-specific risk reduction.
  • Prioritize clustered or operationally critical Linux systems using DLM.
  • Avoid assuming a workaround unless your Linux vendor documents one.

Validation and detection

  • Inventory Linux hosts and record running kernel versions.
  • Identify systems where DLM is enabled, loaded, or operationally required.
  • Compare installed kernels against vendor advisories for CVE-2024-47809.
  • Verify kernel changelogs include the referenced DLM null dereference fix.
  • Confirm no unsupported custom kernel lacks the stable patch.
Prepared
Confidence
high
Sources
7

Public sources used

Based on public source material and reviewed before publication.

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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cwe · low confidence lookup

CWE-476: Exact CWE lookup

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cve · low confidence lookup

CVE-2024-47809 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/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
6Source 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
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2024-47809Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/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
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux43279e5376017c40b4be9af5bc79cbb4ef6f53d7, 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, 43279e5376017c40b4be9af5bc79cbb4ef6f53d7, 43279e5376017c40b4be9af5bc79cbb4ef6f53d7unaffected
LinuxLinux2.6.30, 0, 5.15.209, 6.1.167, 6.6.66, 6.12.5, 6.13affected
Weakness

CWE details

CWE-476

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

CWE-476 · source CWE mapping

NULL Pointer Dereference

NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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