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CVE Record

CVE-2026-43019: Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync hci_conn lookup and field access must be covered by hdev lock in set_cig_params_sync, otherwise it's possible it is freed concurrently. Take hdev lock to prevent hci_conn from being deleted or modified concurrently. Just RCU lock is not suitable here, as we also want to avoid "tearing" in the configuration.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A race condition in the Linux Bluetooth subsystem can leave the kernel using a connection object after another operation frees it. A successful local attack could potentially compromise confidentiality, integrity, and availability. Exact exposure depends on the installed kernel and distributor backports.

Executive priority

Treat as a high-priority kernel update, especially for shared endpoints or systems allowing untrusted local access. It is not evidence of an internet-exploitable emergency or known active exploitation. Use an accelerated, tested patch cycle based on distributor confirmation.

Technical view

set_cig_params_sync can look up and access an hci_conn without holding the hdev lock, allowing concurrent deletion or modification and a potential use-after-free. The documented correction protects the lookup and field access with the hdev lock. RCU alone is insufficient because configuration tearing must also be prevented.

Likely exposure

Prioritize Linux systems with Bluetooth enabled or used and kernels identified as affected, including listed 6.6 through 7.0 branches. The supplied version data is irregular, so version numbers alone may misclassify distributor kernels containing backported fixes. Confirm patch status with the kernel supplier.

Exploitation context

The CVSS 3.1 assessment is 7.8: local access, low complexity, low privileges, and no user interaction, with potentially high confidentiality, integrity, and availability impact. The bundle does not establish active exploitation, and the CVE is not listed as KEV.

Researcher notes

The core issue is an hci_conn lifetime and consistency race in set_cig_params_sync. Concurrent deletion or modification can produce a use-after-free or torn configuration. The supplied record provides stable-kernel correction commits but no public exploit evidence, reproduction details, CWE assignment, or proof that every listed branch is uniformly affected.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable referenced Linux stable fix.
  • Check distributor guidance because kernel version strings may not reveal backported fixes.
  • Prioritize multi-user systems where untrusted local users can access Bluetooth functionality.
  • Apply normal change controls and test Bluetooth-dependent workloads before broad rollout.

Validation and detection

  • Inventory installed kernel builds and identify systems using Bluetooth functionality.
  • Confirm the applicable fix commit or distributor backport is present in each kernel build.
  • Verify set_cig_params_sync protects hci_conn lookup and access with the hdev lock.
  • After updating, confirm systems boot normally and required Bluetooth workflows still operate.
Prepared
Confidence
high
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

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.

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CVE-2026-43019 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
0ADP providers
6Source links

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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2026-43019Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxa091289218202bc09d9b9caa8afcde1018584aec, a091289218202bc09d9b9caa8afcde1018584aec, a091289218202bc09d9b9caa8afcde1018584aec, a091289218202bc09d9b9caa8afcde1018584aec, a091289218202bc09d9b9caa8afcde1018584aec, 3a273cd0f47dd672d37736e623849374f9ab9ce9, d8570c4c3f2a3e51b3c8b5e6ec898364c5c03062, 6.4.16, 6.5.3unaffected
LinuxLinux6.6, 0, 6.6.143, 6.12.81, 6.18.22, 6.19.12, 7.0affected
Weakness

CWE details

No CWE listed

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