This article provides a detailed analysis of CVE-2025-66409, a security vulnerability affecting Espressif’s ESP-IDF (IoT Development Framework). This vulnerability, if exploited, could lead to an out-of-bounds read, potentially exposing sensitive information or causing unexpected behavior on ESP32 devices.
Overview
CVE-2025-66409 is an out-of-bounds read vulnerability discovered in the ESP-IDF Bluetooth stack. Specifically, when AVRCP (Audio/Video Remote Control Profile) is enabled, a malformed VENDOR DEPENDENT command received from a paired Bluetooth device can cause the stack to access memory locations beyond the boundaries of the allocated buffer. This can occur because the command buffer length is not properly validated before memory access.
Technical Details
The vulnerability resides in the way the ESP-IDF Bluetooth stack handles incoming AVRCP commands. When a VENDOR DEPENDENT command is received, the stack attempts to process the command data. However, if the command is crafted with a malformed length field, the stack may attempt to read data beyond the allocated buffer size. This out-of-bounds read can potentially expose unintended memory content, including sensitive information, or trigger a crash due to invalid memory access.
The affected ESP-IDF versions include:
- 5.5.1
- 5.4.3
- 5.3.4
- 5.2.6
- 5.1.6
- And earlier versions
CVSS Analysis
Currently, the CVSS score for CVE-2025-66409 is not available (N/A). However, due to the potential for information disclosure and denial-of-service, it is likely to be rated as a medium to high severity vulnerability. A full CVSS analysis will be updated once available.
Possible Impact
The exploitation of CVE-2025-66409 can have several potential impacts:
- Information Disclosure: An attacker could potentially read sensitive data stored in memory, such as cryptographic keys or configuration information.
- Denial of Service (DoS): The out-of-bounds read could cause the Bluetooth stack or the entire device to crash, leading to a denial of service.
- Unexpected Behavior: The vulnerability could lead to unpredictable system behavior and potentially enable further exploitation.
Mitigation or Patch Steps
Espressif has released patches to address this vulnerability. It is highly recommended to update your ESP-IDF installation to a patched version. Refer to the following commits and security advisory for more information:
- Update to the latest version of ESP-IDF (recommended).
- Apply the relevant patches from the provided commit links (see References section).
- If updating is not immediately possible, consider disabling AVRCP functionality as a temporary workaround, although this will impact Bluetooth audio/video remote control capabilities.
References
- Commit 075ed218cadb8088155521cd8a795d8a626519fb (github.com)
- Commit 2f788e59ee361eee230879ae2ec9cf5c893fe372 (github.com)
- Commit 798029129a71c802cff0e75eb59f902bca8f1946 (github.com)
- Commit 999710fccf95ae128fe51b5679d6b7c75c50d902 (github.com)
- Commit d5db5f60fc1dcfdd8cd3ee898fdefaa272988ace (github.com)
- Commit daeeba230327176b9627b1caa94acdc54065c4b7 (github.com)
- Espressif Security Advisory GHSA-qhf9-vr2h-jh96 (github.com)
