CVE-2026-54571: CWE-190: Integer Overflow or Wraparound in ESP32Async ESPAsyncWebServer
ESPAsyncWebServer is an asynchronous HTTP and WebSocket server library for ESP32, ESP8266, RP2040 and RP2350. Prior to 3.11.1, the multipart/form-data parser in src/WebRequest.cpp stores _boundaryPosition as an 8-bit value while _parseMultipartPostByte processes the boundary. A remote request containing an exactly 256-byte multipart boundary wraps _boundaryPosition from 255 to zero, prevents the boundary parsing loop from terminating, consumes excessive CPU, and triggers a FreeRTOS watchdog reset on affected ESP32 or ESP8266 devices. This issue is fixed in version 3.11.1.
CVE-2026-54571: CWE-190: Integer Overflow or Wraparound in ESP32Async ESPAsyncWebServer
Description
ESPAsyncWebServer is an asynchronous HTTP and WebSocket server library for ESP32, ESP8266, RP2040 and RP2350. Prior to 3.11.1, the multipart/form-data parser in src/WebRequest.cpp stores _boundaryPosition as an 8-bit value while _parseMultipartPostByte processes the boundary. A remote request containing an exactly 256-byte multipart boundary wraps _boundaryPosition from 255 to zero, prevents the boundary parsing loop from terminating, consumes excessive CPU, and triggers a FreeRTOS watchdog reset on affected ESP32 or ESP8266 devices. This issue is fixed in version 3.11.1.
CVSS v4.0
Score 8.7high
Affected software
ESP32Async
ESPAsyncWebServer
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-15T19:15:27.343Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6aac35b755bf5e2cf5bfecae
Added to database: 09/17/2026, 18:47:19 UTC
Last updated: 09/17/2026, 18:47:19 UTC
Views: 1
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