Description
LibreSSL through 4.4.0 contains a CRLF injection vulnerability in the libcrypto OCSP_sendreq_new() and OCSP_parse_url() functions, which write unvalidated request paths into the OCSP POST request line. Attackers can embed carriage return and line feed characters in a certificate's Authority Information Access OCSP URI to inject HTTP headers or split requests sent to responders and proxies.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| OpenBSD | LibreSSL | ≤ 4.4.0 | — |
Advisories 1
- WID-SEC-2026-4202 LibreSSL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 27, 2026
References
- https://github.com/openbsd/src/commit/d3f7195f4849d8a699cea4a3a67677f4b3dc1591 patch
- https://github.com/openbsd/src/blob/3903c41d301d66facec69f7bf776b182cbc5ed62/lib/libcrypto/ocsp/ocsp_ht.c#L184 technical-description
- LibreSSL 4.4.0 Release Notes release-notes
- https://github.com/libressl/portable product
- VulnCheck Advisory: LibreSSL through 4.4.0 CRLF Injection via OCSP_sendreq_new() Request Line third-party-advisory