Security readout for executives and security teams
Plain-English summary
A nearby attacker may reach a Linux device over Bluetooth Low Energy without credentials or user interaction. The kernel failed to reject certain L2CAP connection requests using an inadequate encryption key size. The supplied CVSS assessment indicates potentially serious confidentiality and integrity impact, although the sources do not describe a demonstrated end-to-end attack.
Executive priority
Treat this as a high-priority proximity risk, especially for mobile, embedded, kiosk, and publicly accessible Linux devices using Bluetooth. Schedule vendor-supported kernel updates promptly, but do not assume internet-wide exposure. Escalate systems handling sensitive data where nearby untrusted persons could obtain Bluetooth reach.
Technical view
Linux L2CAP handling omitted the encryption-key-size check when processing L2CAP_LE_CONN_REQ. The correction returns L2CAP_CR_LE_BAD_KEY_SIZE as required by the cited Bluetooth conformance test. CVSS 3.1 is 8.1 with adjacent access, low complexity, no privileges, no interaction, high confidentiality and integrity impact, and no availability impact.
Likely exposure
Exposure is most plausible on affected Linux systems with Bluetooth Low Energy enabled and reachable by a nearby attacker. The supplied affected-version metadata spans multiple kernel branches but is insufficiently structured to determine precise vulnerable ranges reliably. Confirm status using the running distribution kernel and its vendor guidance.
Exploitation context
The bundle marks this CVE as absent from KEV and provides no evidence of active exploitation or a public exploit. The adjacent-network vector limits attacks to Bluetooth proximity or equivalent radio reach. No prerequisites beyond reachability are established by the supplied CVSS vector, but practical attack outcomes are not documented.
Researcher notes
The evidence establishes a missing key-size validation and its expected protocol rejection result. It does not identify a CWE, minimum accepted key size, proof of concept, observed exploitation, or detailed compromise mechanism. Multiple stable commits indicate branch-specific backports; validate package ancestry rather than comparing version strings alone.
Mitigation direction
- Update to a vendor-supported kernel containing the applicable referenced stable fix.
- Check distribution security guidance to map packaged kernel versions to the upstream fixes.
- Prioritize Bluetooth-enabled endpoints operating in public, shared, or physically accessible locations.
- If updates are delayed, follow vendor guidance for reducing unnecessary Bluetooth exposure.
Validation and detection
- Inventory Linux endpoints with Bluetooth Low Energy enabled or required.
- Record each running kernel and distribution package version.
- Confirm the vendor package incorporates an applicable referenced kernel commit.
- Retest Bluetooth-dependent services after updating the kernel.
- Monitor vendor advisories because the supplied version boundaries are ambiguous.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-2026-43134 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N2.85.2LinuxVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/335071c0c3637064ec250481f589075db44fe4e6CVE reference, Linux
- https://git.kernel.org/stable/c/fa6ad76fa8623c0a50d529cd5726fa5d819a3be4CVE reference, Linux
- https://git.kernel.org/stable/c/9118601ff90b79e8df3c0c98f48ae00c1b02ecefCVE reference, Linux
- https://git.kernel.org/stable/c/481ea39b342c347b6ac029f3d418486280be4e45CVE reference, Linux
- https://git.kernel.org/stable/c/ec91078e132179b04e0c3906b599816c056ceaadCVE reference, Linux
- https://git.kernel.org/stable/c/96581749c7c14fbec32c35728520867929600041CVE reference, Linux
- https://git.kernel.org/stable/c/8dd43f9a9323f9c01bc8246da8d81a4c783c9e97CVE reference, Linux
- https://git.kernel.org/stable/c/138d7eca445ef37a0333425d269ee59900ca1104CVE reference, Linux
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.