Threats affecting pkg:github/LibreSSL

LibreSSL versions up to 4.4.0 contain a memory exhaustion vulnerability in the ocspcheck component. This flaw allows malicious OCSP responders to send unbounded HTTP responses, causing the client to consume excessive memory. Attackers who control the OCSP responder or can intercept unencrypted HTTP AIA OCSP traffic can exploit this by streaming endless headers or body data, resulting in denial of certificate status checks.

CVE-2026-118373 is a vulnerability in LibreSSL's ocspcheck component up to version 4.4.0 that causes cleartext transmission of sensitive OCSP request data. The issue arises because the function url2host() removes the OCSP URL scheme, and http_alloc() only uses TLS for port 443. As a result, OCSP requests sent to HTTPS responder URLs on non-443 ports are transmitted without encryption, exposing certificate serial numbers, issuer hashes, and nonces to on-path attackers.

LibreSSL versions up to 4.4.0 contain a CRLF injection vulnerability in the ocspcheck utility. This flaw allows attackers to inject HTTP headers by embedding carriage return and line feed sequences in a certificate's AIA OCSP URI path. The vulnerability arises because the url2host() function copies the path without filtering control characters, and http_open() includes this path in the POST request line, enabling header injection or request splitting to the OCSP responder.

LibreSSL versions up to 4.4.0 have a CRLF injection vulnerability in the libcrypto OCSP_sendreq_new() and OCSP_parse_url() functions. This flaw allows attackers to inject carriage return and line feed characters into the OCSP request line by embedding them in a certificate's Authority Information Access OCSP URI. This can lead to HTTP header injection or request splitting when communicating with OCSP responders or proxies.