CVE-2026-62966

ESPAsyncWebServer is an asynchronous HTTP and WebSocket server library for ESP32, ESP8266, RP2040 and RP2350. Prior to version 3.11.2, the multipart parser in `src/WebRequest.cpp` frees `_itemBuffer` and sets it to NULL when `BOUNDARY_OR_DATA` matches the closing boundary of a file part, before confirming the following terminator, while leaving `_itemIsFile` true. If the next byte is neither the final closing dashes nor a clean CRLF, the `DASH3_OR_RETURN2` or `EXPECT_FEED2` rewind branch re-injects provisionally consumed bytes through `itemWriteByte`. Because `_itemIsFile` remains true, `_itemBuffer`[`_itemBufferIndex`++] writes through a null pointer. On ESP32 this causes a `StoreProhibited` exception, panic and device reboot, producing remote denial of service. A route with a non-trivial body/upload handler, such as a file-upload or web-OTA endpoint, must be present. This issue is fixed in version 3.11.2.

• CWE-476
• CWE-672

• https://github.com/ESP32Async/ESPAsyncWebServer/commit/4efbd35e597d91f01749f2d4a14bb78fba8ea02e
• https://github.com/ESP32Async/ESPAsyncWebServer/security/advisories/GHSA-8m8p-vhxc-jmjw
• https://github.com/ESP32Async/ESPAsyncWebServer/tree/v3.11.2

Published

Oct 30, 2026

Last Modified

Oct 30, 2026

Status

Deferred

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-62958libriscv is a RISC-V sandbox and emulator. Prior to 1.18, a …7.9
• CVE-2026-62959Coturn is a free open source implementation of TURN and STUN…8.2
• CVE-2026-6296Heap buffer overflow in ANGLE in Google Chrome prior to 147.…9.6
• CVE-2026-62960Git for Windows is the Windows port of Git. Prior to 2.55.0.…7.4
• CVE-2026-62963Centrifugo is an open-source scalable real-time messaging se…8.7
• CVE-2026-62965SABnzbd is an open source automated Usenet download tool. Pr…7
• CVE-2026-62967ZTNET is a ZeroTier web UI for private controllers with mult…8.1
• CVE-2026-62968Dream Displays provides in-game screens for streaming videos…8.7
• CVE-2026-6297Use after free in Proxy in Google Chrome prior to 147.0.7727…8.3
• CVE-2026-62979jack lets users share media libraries through their Radarr/S…8.4
• CVE-2026-6298Heap buffer overflow in Skia in Google Chrome prior to 147.0…4.3
• CVE-2026-62982Glances is an open-source system cross-platform monitoring t…8.8