Issue summary: An application using the OpenSSL HTTP client API functions may trigger an out-of-bounds read if the 'no_proxy' environment variable is set and the host portion of the authority component of the HTTP URL is an IPv6 address. Impact summary: An out-of-bounds read can trigger a crash which leads to Denial of Service for an application. The OpenSSL HTTP client API functions can be used directly by applications but they are also used by the OCSP client functions and CMP (Certificate Management Protocol) client implementation in OpenSSL. However the URLs used by these implementations are unlikely to be controlled by an attacker. In this vulnerable code the out of bounds read can only trigger a crash. Furthermore the vulnerability requires an attacker-controlled URL to be passed from an application to the OpenSSL function and the user has to have a 'no_proxy' environment variable set. For the aforementioned reasons the issue was assessed as Low severity. The vulnerable code was introduced in the following patch releases: 3.0.16, 3.1.8, 3.2.4, 3.3.3, 3.4.0 and 3.5.0. The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as the HTTP client implementation is outside the OpenSSL FIPS module boundary.
https://github.com/openssl/openssl/commit/bbf38c034cdabd0a13330abcc4855c866f53d2e0
https://github.com/openssl/openssl/commit/89e790ac431125a4849992858490bed6b225eadf
https://github.com/openssl/openssl/commit/7cf21a30513c9e43c4bc3836c237cf086e194af3
https://github.com/openssl/openssl/commit/654dc11d23468a74fc8ea4672b702dd3feb7be4b
https://github.com/openssl/openssl/commit/2b4ec20e47959170422922eaff25346d362dcb35