schreibfaul1 ESP32-audioI2S 3.4.5 src/Audio.cpp htmlToUTF8 heap-based overflow

Summaryinfo

A vulnerability classified as critical has been found in schreibfaul1 ESP32-audioI2S 3.4.5. The impacted element is the function htmlToUTF8 of the file src/Audio.cpp. Performing a manipulation results in heap-based overflow. This vulnerability is reported as CVE-2026-51270. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, was found in schreibfaul1 ESP32-audioI2S 3.4.5. This affects the function htmlToUTF8 of the file src/Audio.cpp. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as 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(). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

schreibfaul1 ESP32-audioI2S 3.4.5 has a heap-based buffer overflow vulnerability in the htmlToUTF8() HTML entity decoding function. The function parses attacker-controlled malicious HTML entities and uses memmove and memcpy to rearrange string content without validating buffer remaining size and boundary limits. Crafted oversized HTML entity strings can trigger heap out-of-bounds write, allowing remote code execution, memory information leakage, service crash or privilege escalation.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-51270 since 06/07/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for 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.

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Productinfo

Vendor

• schreibfaul1

Name

• ESP32-audioI2S

Version

• 3.4.5

Website

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

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