# CVE-2026-87961: ESP32-audioI2S heap out-of-bounds read in ID3 header processing

Source: https://junglewise.ai/threats/cve-2026-87961-esp32-audioi2s-heap-out-of-bounds-read-in-id3-header-processing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-10. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-87961 · Severity: high · CVSS 7.1 · Published 2026-09-10

ESP32-audioI2S is a library that enables ESP32 microcontrollers to play audio files from various sources including SD cards and HTTP streams. A vulnerability in its ID3 metadata parsing allows attackers to craft malicious MP3 files or streams that cause the device to crash or leak sensitive data from device memory, potentially exposing credentials or other confidential information stored on the chip.

Technologies: [Schreibfaul1 ESP32-audioI2S](https://junglewise.ai/threats/technologies/esp32-audioi2s). Vendors: [Schreibfaul1](https://junglewise.ai/threats/vendors/schreibfaul1).

## Quick answers

**Is CVE-2026-87961 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-87961 being exploited in the wild.

**How severe is CVE-2026-87961?** High severity, with a CVSS score of 7.1, published 10 September 2026.

**Which products and versions are affected?** Schreibfaul1 ESP32-audioI2S 3.4.4 through 4.0.0.

**Is there a fix for CVE-2026-87961?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-87961 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-87961?** Check whether you run Schreibfaul1 ESP32-audioI2S at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a heap-based out-of-bounds read in the read_ID3_Header function caused by a shadowed length parameter in ID3 synchronized-lyrics processing. When processing a crafted MP3 file or HTTP audio stream with oversized frame size declarations, the vulnerable code reads past allocated buffer boundaries. An attacker can exploit this by hosting a malicious audio file on a web server or providing it via other sources; no authentication is required. Successful exploitation results in device crashes (denial of service) or potential exposure of adjacent heap memory containing sensitive data. A patch is expected to address the shadowed parameter issue.

## Affected products

- schreibfaul1 ESP32-audioI2S 3.4.4 through 4.0.0

## Timeline

- 2026-09-10: disclosed

## References

- [https://github.com/schreibfaul1/ESP32-audioI2S](https://github.com/schreibfaul1/ESP32-audioI2S)
- [https://github.com/schreibfaul1/ESP32-audioI2S/blob/490ff729eca344f06581f3e9bda9cfba948fd5a1/src/Audio.cpp](https://github.com/schreibfaul1/ESP32-audioI2S/blob/490ff729eca344f06581f3e9bda9cfba948fd5a1/src/Audio.cpp)

## Related threats

- [schreibfaul1 ESP32-audioI2S heap overflow in latinToUTF8](https://junglewise.ai/threats/cve-2026-51272-schreibfaul1-esp32-audioi2s-heap-overflow-in-latintoutf8)
- [schreibfaul1 ESP32-audioI2S heap buffer overflow in ID3v2 APIC parsing](https://junglewise.ai/threats/cve-2026-51275-schreibfaul1-esp32-audioi2s-heap-buffer-overflow-in-id3v2-apic)
- [schreibfaul1 ESP32-audioI2S heap overflow in SYLT parser](https://junglewise.ai/threats/cve-2026-51274-schreibfaul1-esp32-audioi2s-heap-overflow-in-sylt-parser)
- [schreibfaul1 ESP32-audioI2S heap overflow in showID3Tag](https://junglewise.ai/threats/cve-2026-51273-schreibfaul1-esp32-audioi2s-heap-overflow-in-showid3tag)
- [schreibfaul1 ESP32-audioI2S heap buffer overflow in read_WAV_Header](https://junglewise.ai/threats/cve-2026-51271-schreibfaul1-esp32-audioi2s-heap-buffer-overflow-in-read-wav)