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.
Advisories

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Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 18 May 2026 13:15:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:espressif:arduino-esp32:*:-:*:*:*:*:*:*

Wed, 13 May 2026 16:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 13 May 2026 00:00:00 +0000

Type Values Removed Values Added
First Time appeared Espressif
Espressif arduino-esp32
Vendors & Products Espressif
Espressif arduino-esp32

Tue, 12 May 2026 22:15:00 +0000

Type Values Removed Values Added
Description 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.
Title arduino-esp32: Stack buffer overflow in WebServer multipart boundary parsing leads to remote crash potential RCE
Weaknesses CWE-121
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-13T14:24:52.597Z

Reserved: 2026-04-30T16:44:48.378Z

Link: CVE-2026-42854

cve-icon Vulnrichment

Updated: 2026-05-13T14:24:48.901Z

cve-icon NVD

Status : Analyzed

Published: 2026-05-12T22:16:34.930

Modified: 2026-05-18T13:09:58.927

Link: CVE-2026-42854

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-12T23:45:25Z

Weaknesses