schreibfaul1 ESP32-audioI2S 3.4.5 src/Audio.cpp Audio::openai_speech heap-based overflow

Summaryinfo

A vulnerability identified as critical has been detected in schreibfaul1 ESP32-audioI2S 3.4.5. This vulnerability affects the function Audio::openai_speech of the file src/Audio.cpp. The manipulation leads to heap-based overflow. This vulnerability is listed as CVE-2026-51263. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in schreibfaul1 ESP32-audioI2S 3.4.5. It has been rated as critical. This issue affects the function Audio::openai_speech of the file src/Audio.cpp. The manipulation with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

schreibfaul1 ESP32-audioI2S 3.4.5 is vulnerable to Buffer Overflow. The Audio::openai_speech function in the Audio library manually constructs JSON request bodies and HTTP request headers by directly concatenating externally controllable input and instructions strings without effective length restriction and boundary validation. An unauthenticated remote attacker can send oversized malicious string data to trigger a heap buffer overflow during string splicing, resulting in memory corruption.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-51263 since 06/07/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/28/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• schreibfaul1

Name

• ESP32-audioI2S

Version

• 3.4.5

Website

• Product: https://github.com/schreibfaul1/ESP32-audioI2S/

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