espressif arduino-esp32 up to 3.3.7 Multipart Form stack-based overflow

Summaryinfo

A vulnerability, which was classified as critical, was found in espressif arduino-esp32 up to 3.3.7. This affects an unknown part of the component Multipart Form Handler. Executing a manipulation can lead to stack-based overflow. This vulnerability is tracked as CVE-2026-42854. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in espressif arduino-esp32 up to 3.3.7 and classified as critical. This vulnerability affects some unknown functionality of the component Multipart Form Handler. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

arduino-esp32 is an Arduino core for the ESP32, ESP32-S2, ESP32-S3, ESP32-C3, ESP32-C6 and ESP32-H2 microcontrollers. Prior to 3.3.8, the WebServer multipart form parser in arduino-esp32 allocates a Variable Length Array (VLA) on the stack whose size is derived from an attacker-controlled HTTP header field (Content-Type: multipart/form-data; boundary=...) without enforcing any length limit. Sending a boundary string longer than ~8000 characters overflows the 8192-byte task stack of the loopTask, causing a crash and potential remote code execution. This vulnerability is fixed in 3.3.8.

The advisory is available at github.com. This vulnerability was named CVE-2026-42854 since 04/30/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available.

Upgrading to version 3.3.8 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• espressif

Name

• arduino-esp32

Version

• 3.3.0
• 3.3.1
• 3.3.2
• 3.3.3
• 3.3.4
• 3.3.5
• 3.3.6
• 3.3.7

Website

• Product: https://github.com/espressif/arduino-esp32/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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