CVE-2026-81508 in ESP-IDF
Summary
by MITRE • 09/24/2026
ESF-IDF is the Espressif Internet of Things (IOT) Development Framework. In 5.5.5, 6.0.1, and 6.1, the BlueDroid A2DP sink function btc_a2dp_sink_handle_inc_media() reads a timestamp field from the received media buffer before validating that the packet layout contains the field. A paired BR/EDR audio source within radio range can send a malformed A2DP media packet to a build with BlueDroid Classic Bluetooth and A2DP sink support enabled, causing an out-of-bounds read into adjacent heap memory and limited disclosure of heap contents. Arbitrary memory disclosure and code execution are not established.
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Analysis
by VulDB Data Team • 09/25/2026
The vulnerability identified in the Espressif Internet of Things Development Framework affects versions 5.5.5, 6.0.1, and 6.1 within the BlueDroid stack's Advanced Audio Distribution Profile sink implementation. Specifically, the function btc_a2dp_sink_handle_inc_media exhibits a critical logic error during the processing of incoming media packets from paired Bluetooth Classic audio sources. The core technical flaw lies in the sequence of operations performed on received data buffers; the code attempts to read a timestamp field directly from the packet payload before verifying that the packet structure actually contains such a field or validating the overall integrity and layout of the incoming A2DP media packet. This premature access assumes a fixed packet format without confirming that the sender has adhered to the expected protocol specifications, creating a classic case of improper input validation where trust is placed in external data structures before they are sanitized or verified for structural correctness.
From an operational perspective, this flaw allows any Bluetooth device within radio range that is paired with the affected Espressif device to trigger an out-of-bounds read condition. By sending a malformed A2DP media packet that lacks the expected timestamp field or has a truncated header, an attacker can force the BlueDroid stack to access memory locations adjacent to the allocated buffer for the incoming data. This results in limited disclosure of heap contents, as the application reads uninitialized or unrelated memory into the processing pipeline. While this does not immediately lead to arbitrary code execution due to the read-only nature of the flaw and potential mitigations within the operating system's memory management unit, it constitutes a significant information leakage vulnerability that can be leveraged for further reconnaissance or potentially chained with other vulnerabilities in more complex attack scenarios involving heap manipulation techniques.
The security implications align closely with Common Weakness Enumeration CWE-125, which describes Out-of-bounds Read, as the application accesses data beyond the intended buffer boundary without proper bounds checking prior to access. Furthermore, this vulnerability maps to MITRE ATT&CK technique T1083, File and Directory Discovery, in the context of memory disclosure where an attacker seeks to extract sensitive information from the device's volatile memory space. The attack vector is classified as Local or Adjacent Network via Bluetooth BR/EDR, requiring physical proximity and a paired connection state, which limits the scope but increases the severity for devices deployed in trusted local environments such as smart homes or industrial IoT setups where pairing is common.
To mitigate this vulnerability, Espressif has released updated versions of the ESP-IDF framework that correct the order of operations within the btc_a2dp_sink_handle_inc_media function to ensure strict validation of packet structure before any field extraction occurs. Users running affected versions should immediately upgrade to a patched release where input validation precedes data access. In environments where immediate patching is not feasible, network segmentation strategies can be employed to restrict Bluetooth Classic connectivity to only known and trusted devices, thereby reducing the attack surface presented by unpaired or unauthorized peripherals attempting to interact with the A2DP sink interface. Additionally, enabling strict memory protection features on the underlying microcontroller architecture can help contain potential information leaks should similar flaws exist in other parts of the stack.