Vulnerability · Published Jun 26, 2025 · Assigned by GitHub_M
CVE-2025-53007arduino-esp32 vulnerable to CRLF injection in WebServer.cpp
High 8.9
In plain English
A high-severity security flaw in arduino-esp32 from espressif. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities).
Official description
arduino-esp32 provides an Arduino core for the ESP32. Versions prior to 3.3.0-RC1 and 3.2.1 contain a HTTP Response Splitting vulnerability. The `sendHeader` function takes arbitrary input for the HTTP header name and value, concatenates them into an HTTP header line, and appends this to the outgoing HTTP response headers. There is no validation or sanitization of the `name` or `value` parameters before they are included in the HTTP response. If an attacker can control the input to `sendHeader` (either directly or indirectly), they could inject carriage return (`\r`) or line feed (`\n`) characters into either the header name or value. This could allow the attacker to inject additional headers, manipulate the structure of the HTTP response, potentially inject an entire new HTTP response (HTTP Response Splitting), and/or ause header confusion or other HTTP protocol attacks. Versions 3.3.0-RC1 and 3.2.1 contain a fix for the issue.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| espressif | arduino-esp32 | < 3.2.1>= 3.3.0-alpha1, < 3.3.0-RC1 |
Weakness: CWE-113 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
References
- https://github.com/espressif/arduino-esp32/security/advisories/GHSA-5476-9jjq-563m x_refsource_CONFIRM
- https://github.com/espressif/arduino-esp32/commit/21640ac82a1bb5efa8cf0b3841be1ac80add6785 x_refsource_MISC
- https://github.com/espressif/arduino-esp32/blob/9e61fa7e4bce59c05cb17c15b11b53b9bafca077/libraries/WebServer/src/WebServer.cpp#L504-L521 x_refsource_MISC
- https://github.com/espressif/arduino-esp32/blob/9e61fa7e4bce59c05cb17c15b11b53b9bafca077/libraries/WebServer/src/WebServer.cpp#L577-L582 x_refsource_MISC