Is there a public exploit for CVE-2026-62966?

No public exploit for CVE-2026-62966 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-62966?

CVE-2026-62966 scores CVSS 7.5 (v3.1), rated high.

7.5 High

ESPAsyncWebServer is an asynchronous HTTP and WebSocket server library for ESP32, ESP8266, RP2040 and RP2350.

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 BOUNDARYORDATA 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 DASH3ORRETURN2 or EXPECTFEED2 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.

Assessment

CVSS: 7.5 (v3.1)
Severity: High
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 30 October 2026
Last updated: 30 October 2026
Weakness: CWE-476, CWE-672
Assigner: security-advisories@github.com

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

At the source

References

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