A flaw was found in libssh. A remote attacker, by controlling client configuration files or known_hosts files, could craft specific hostnames that when processed by the match_pattern() function can lead to inefficient regular expression backtracking. This can cause timeouts and resource exhaustion, resulting in a Denial of Service (DoS) for the client.
{
"availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
"binaries": [
{
"binary_version": "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6",
"binary_name": "libssh-4"
},
{
"binary_version": "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6",
"binary_name": "libssh-gcrypt-4"
}
]
}