Format string vulnerability in the mod_proxy hook functions function in ssl_engine_log.c in mod_ssl before 2.8.19 for Apache before 1.3.31 may allow remote attackers to execute arbitrary messages via format string specifiers in certain log messages for HTTPS that are handled by the ssl_log function.

The dbm and shm session cache code in mod_ssl before 2.8.7-1.3.23, and Apache-SSL before 1.3.22+1.46, does not properly initialize memory using the i2d_SSL_SESSION function, which allows remote attackers to use a buffer overflow to execute arbitrary code via a large client certificate that is signed by a trusted Certificate Authority (CA), which produces a large serialized session.