LiveActive security incident?Get immediate response
CVE Record

CVE-2024-56654: Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating The usage of rcu_read_(un)lock while inside list_for_each_entry_rcu is not safe since for the most part entries fetched this way shall be treated as rcu_dereference: Note that the value returned by rcu_dereference() is valid only within the enclosing RCU read-side critical section [1]_. For example, the following is **not** legal:: rcu_read_lock(); p = rcu_dereference(head.next); rcu_read_unlock(); x = p->address; /* BUG!!! */ rcu_read_lock(); y = p->data; /* BUG!!! */ rcu_read_unlock();

MediumCVSS 5.5Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel Bluetooth flaw that can let a local, low-privileged user crash the system. It is not described as remote code execution or data theft. The business impact is mainly availability: affected hosts may be vulnerable to denial of service if they run impacted kernels and expose the Bluetooth stack.

Executive priority

Treat as a routine but real availability risk. Patch through normal kernel maintenance, prioritizing shared Linux systems, endpoints, and any environment where untrusted local users can run code.

Technical view

The issue is in Linux Bluetooth hci_event handling. The CVE describes unsafe RCU read-side locking while iterating with list_for_each_entry_rcu, where entries must remain inside the enclosing critical section. The CVSS vector is local, low complexity, low privileges, no user interaction, and high availability impact.

Likely exposure

Exposure is most likely on Linux systems running affected kernel versions or downstream backports without the referenced stable fixes, especially where Bluetooth support is enabled and local users can execute code.

Exploitation context

The source bundle does not show CISA KEV listing or cited active exploitation. CVSS indicates local exploitation with low privileges and no user interaction. Available evidence supports denial of service impact, not confidentiality or integrity loss.

Researcher notes

The affected-version data is kernel-centric and commit-oriented, not distribution-package-specific. Analysis should focus on Bluetooth hci_event RCU lifetime handling and whether downstream kernels have backported the stable fixes. No exploit details are provided in the source bundle.

Mitigation direction

  • Apply Linux kernel updates that include the referenced stable fixes.
  • Use distribution vendor advisories to identify fixed backported kernel packages.
  • Prioritize systems with Bluetooth enabled and local multi-user access.
  • Reboot into the updated kernel after patch installation.
  • If Bluetooth is unnecessary, evaluate disabling it through approved platform controls.

Validation and detection

  • Inventory Linux kernel versions across servers, endpoints, and appliances.
  • Confirm whether installed vendor kernels include the referenced stable commits or backports.
  • Identify systems with Bluetooth hardware, modules, or services enabled.
  • Verify patched systems are actually running the updated kernel after reboot.
  • Track vendor advisories because package-level fixed versions are not provided here.
Prepared
Confidence
medium
Sources
5

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2024-56654 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
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
4Source 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-2024-56654Attack 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
LinuxLinuxa0bfde167b506423111ddb8cd71930497a40fc54, a0bfde167b506423111ddb8cd71930497a40fc54, a0bfde167b506423111ddb8cd71930497a40fc54, b475c1109251e30ec21fb574d72a1c71a4ab0039, 2ccde10127447c1a5caad8469fede945bdb62fdf, 6.4.16, 6.5.3unaffected
LinuxLinux6.6, 0, 6.6.67, 6.12.6, 6.13affected
Weakness

CWE details

No CWE listed

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