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Description

ESPAsyncWebServer is an asynchronous HTTP and WebSocket server library for ESP32, ESP8266, RP2040 and RP2350. In versions up to and including 3.7.8, a CRLF (Carriage Return Line Feed) injection vulnerability exists in the construction and output of HTTP headers within `AsyncWebHeader.cpp`. Unsanitized input allows attackers to inject CR (`\r`) or LF (`\n`) characters into header names or values, leading to arbitrary header or response manipulation. Manipulation of HTTP headers and responses can enable a wide range of attacks, making the severity of this vulnerability high. A fix is available at pull request 211 and is expected to be part of version 3.7.9.

PUBLISHED Reserved 2025-06-25 | Published 2025-06-27 | Updated 2025-06-27 | Assigner GitHub_M




HIGH: 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Problem types

CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')

CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')

Product status

<= 3.7.8
affected

References

github.com/...Server/security/advisories/GHSA-87j8-6f7g-h8wh

github.com/ESP32Async/ESPAsyncWebServer/pull/211

github.com/...ede29854232af1b24f089b1/src/AsyncWebHeader.cpp

cve.org (CVE-2025-53094)

nvd.nist.gov (CVE-2025-53094)

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