CVE-2024-45431 Overview
CVE-2024-45431 affects the OpenSynergy BlueSDK Bluetooth stack through version 6.x. The flaw stems from improper validation of the remote Logical Link Control and Adaptation Protocol (L2CAP) channel identifier (CID). An attacker within Bluetooth range can create an L2CAP channel with a null identifier assigned as the remote CID. The vulnerability is tracked under CWE-20: Improper Input Validation and forms part of the PerfektBlue advisory disclosed by PCA Cybersecurity. BlueSDK is widely deployed in automotive infotainment systems and embedded devices, expanding the potential attack surface.
Critical Impact
An unauthenticated attacker within Bluetooth range can establish an L2CAP channel using a null remote CID, leading to information exposure and abnormal stack state within affected devices.
Affected Products
- OpenSynergy BlueSDK (Blue SDK) versions through 6.x
- Automotive infotainment platforms integrating BlueSDK
- Embedded devices and IoT products bundling the BlueSDK Bluetooth stack
Discovery Timeline
- 2025-09-12 - CVE-2024-45431 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-45431
Vulnerability Analysis
The vulnerability resides in the BlueSDK L2CAP layer, which handles channel setup between paired or connecting Bluetooth peers. L2CAP relies on channel identifiers to demultiplex data between concurrent logical channels on the same ACL link. BlueSDK fails to validate that the remote CID supplied during channel establishment is non-zero and within the reserved range. As a result, the stack accepts a null remote CID and instantiates the channel state. The Bluetooth Core Specification reserves CID 0x0000 as the null identifier, and it must never be used for an active channel. Accepting it leaves the stack in a state that violates protocol assumptions and can be leveraged for downstream attacks referenced in the PerfektBlue advisory.
Root Cause
The root cause is missing input validation on the L2CAP configuration request path. The stack does not enforce that the remote CID falls outside reserved values before allocating channel context and returning success to the peer. This mishandling is consistent with CWE-20: Improper Input Validation.
Attack Vector
An attacker within Bluetooth radio range issues an L2CAP connection request or configuration exchange advertising CID 0x0000 as the source channel identifier. BlueSDK accepts the request and registers the channel. Subsequent L2CAP packets referencing the null CID are processed, enabling the attacker to probe stack behavior and, per the PerfektBlue research, chain the primitive with other flaws. No user interaction or prior pairing authorization is required by the specification path targeted here.
No verified public proof-of-concept code is available. See the PCA Cybersecurity PerfektBlue advisory for the coordinated technical writeup.
Detection Methods for CVE-2024-45431
Indicators of Compromise
- L2CAP signaling packets containing a source CID of 0x0000 observed in Bluetooth captures.
- Unexpected L2CAP channel state entries referencing the null identifier in device logs or diagnostic traces.
- Repeated L2CAP connection or configuration requests from untrusted Bluetooth peers targeting infotainment or embedded devices running BlueSDK.
Detection Strategies
- Inspect Bluetooth HCI snoop logs from vehicles and embedded devices for L2CAP frames using reserved CID values.
- Perform software bill of materials (SBOM) analysis to identify products bundling OpenSynergy BlueSDK version 6.x or earlier.
- Correlate vendor firmware advisories with fielded device inventories to prioritize devices that have not received the PerfektBlue remediation.
Monitoring Recommendations
- Enable vendor-provided Bluetooth stack diagnostics and forward logs to a centralized SIEM for anomaly review.
- Monitor for unexpected Bluetooth pairing attempts and repeated L2CAP signaling errors on managed devices.
- Track advisories from OpenSynergy and downstream OEMs for out-of-band firmware updates addressing PerfektBlue.
How to Mitigate CVE-2024-45431
Immediate Actions Required
- Identify all products in the environment that embed OpenSynergy BlueSDK using vendor documentation and SBOM data.
- Contact device OEMs to obtain firmware updates that include the OpenSynergy PerfektBlue fixes.
- Disable Bluetooth on affected devices where the feature is not required for operations.
- Restrict device discoverability and require confirmed user consent before accepting new pairings.
Patch Information
OpenSynergy has issued fixed builds of BlueSDK addressing the PerfektBlue cluster of vulnerabilities. Because BlueSDK ships as a licensed component inside third-party products, patch delivery depends on the OEM integrating the corrected version into device firmware. Consult the PCA Cybersecurity PerfektBlue advisory and the OpenSynergy homepage for coordination details and update availability.
Workarounds
- Turn Bluetooth off on affected devices when not required, especially in high-risk environments such as parked vehicles.
- Set Bluetooth to non-discoverable mode and refuse pairing requests from unknown peers.
- Physically limit exposure by keeping affected devices outside the Bluetooth radio range of untrusted parties until firmware updates are applied.
# Configuration example: verify Bluetooth is disabled on a Linux-based embedded host
rfkill list bluetooth
rfkill block bluetooth
systemctl disable --now bluetooth.service
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
