Bluetooth controller in Zephyr firmware: identifiers and CRA notes

What it is

Bluetooth controller

• Repository

Notes on this component

The link layer: advertising, scanning, connection handling and the radio timing. CVE family is link-layer packet handling reachable by anything in radio range. This row is keyed on CONFIG_BT_LL_SW_SPLIT, Zephyr's own open-source link layer. CONFIG_BT_CTLR is not used because it is set whichever controller is chosen: a build with Nordic's SoftDevice Controller (CONFIG_BT_LL_SOFTDEVICE) sets it too, and carries none of this code. The virtual symbol HAS_BT_CTLR is not used for the same reason: Zephyr's Kconfig says every local link-layer implementation selects it, vendor ones included. Zephyr's controller/Kconfig was read at v4.4.0 and v3.7.0 on 11 October 2026; BT_LL_SW_SPLIT exists in both. Advisories filed against the link layer include CVE-2026-9263 (an undersized time-offset segment header drives an out-of-bounds read in the controller's ISOAL framed receive path, fixed in 4.3.1 and 4.4.1), CVE-2024-4785 (a missing check in LL_CONNECTION_UPDATE_IND leads to a division by zero, affecting 3.6 and earlier) and CVE-2021-3433 (an invalid channel map in CONNECT_IND deadlocks the controller, fixed in 2.6.0). Anything in radio range reaches all three without pairing first.

Where it hides in a firmware SBOM

It is compiled into the kernel image when CONFIG_BT_LL_SW_SPLIT is y. It does not appear in west spdx output; the only trace is the .config file in your build directory.

The identifiers we assign

CPEthe product name vulnerability databases use to say what a flaw affects

cpe:2.3:o:zephyrproject:zephyr:{version}:*:*:*:*:*:*:*

{version} is filled in from your build. The version is the same as your Zephyr version.

The SBOM check adds these identifiers to a component your build listed without them.

Honest gaps

Vendor: zephyrproject.

This row has no PURL.

Where this row comes from

https://github.com/zephyrproject-rtos/zephyr/blob/v4.4.0/subsys/bluetooth/controller/Kconfig
Checked on 11 October 2026.

Known vulnerabilities

Not checked yet

Vulnerability data changes daily. Check the version you ship in the SBOM check.

CRA notes

• List this component in your SBOM. Annex I, Part II (1): Identify and document components and vulnerabilities, including an SBOMKnow what is in your product. Identify and document its components and their vulnerabilities, including by producing a software bill of materials (SBOM) in a common machine-readable format that covers at least the top-level dependencies.
• Ship the version with no known exploitable vulnerabilities at release. Annex I, Part I (2(a)): Made available without known exploitable vulnerabilitiesWhen you place a release on the market, it must not ship with known vulnerabilities that can be exploited in your product. "Exploitable" means an attacker could effectively use it under practical operating conditions (Article 3(41)), not only in theory or in a lab. The Commission's draft guidance (C(2026) 5252, points 231 to 237; a draft, not binding) gives three ways a vulnerability is "known". One: it is listed in a relevant public vulnerability database, such as the European vulnerability database (EUVD) or another prominent one. Two: you learned of it from information that is not public, for example a security researcher's coordinated disclosure or your own testing and analysis; a vulnerability you know about and have not disclosed still counts. Three: it has been publicly and prominently reported in reliable media, whether specialist security publications or general news. A report is not yet proof: it does not by itself mean the vulnerability can be exploited in practice or applies to your product, so investigate promptly and confirm whether it does. A limited time may pass between the first report and that confirmation. If a vulnerability becomes known shortly before release, you decide from your cybersecurity risk assessment whether the release can go out or the vulnerability must be fixed first. Weigh its severity, exploitability and potential impact, and the risks to the product once in use; you may also weigh the risks of delaying the release, for example because it fixes other exploitable vulnerabilities. After release, the Part II vulnerability handling requirements still apply. Check your components against vulnerability databases before each release, and fix or justify what you find.
• An SBOM without this subsystem under-reports what is in the image. Annex I, Part II (1): Identify and document components and vulnerabilities, including an SBOMKnow what is in your product. Identify and document its components and their vulnerabilities, including by producing a software bill of materials (SBOM) in a common machine-readable format that covers at least the top-level dependencies.

Source: Annex I of Regulation (EU) 2024/2847 (Cyber Resilience Act), legal state 2026.10.13-1.

Related Zephyr components

No related components yet.

Guides that mention Bluetooth controller

• The CRA for ESP-IDF teams: real CPEs out of the box, and the parts they do not cover

Next step

Declarable prepares documentation for you to review. It is not legal advice and not certification. You sign your own declaration of conformity.