CVE-2026-55766

A flaw was found in guzzlehttp/psr7, a PHP library for HTTP messages. This vulnerability allows a remote attacker to inject arbitrary header lines into serialized HTTP/1.x messages. The flaw stems from the library's failure to reject carriage return CR and line feed LF characters in HTTP start-li...

CVE-2026-55766

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Prior to 2.12.1, guzzlehttp/psr7 did not reject CR/LF characters in certain first-party HTTP start-line fields: the request method, protocol version, and response reason phrase. If an application placed attacker-controlled dat...

CVE-2026-55766

guzzlehttp/psr7 is a PSR-7 HTTP message library implementation in PHP. Prior to 2.12.1, guzzlehttp/psr7 did not reject CR/LF characters in certain first-party HTTP start-line fields: the request method, protocol version, and response reason phrase. If an application placed attacker-controlled dat...