CVE-2023-27538: High severity IBM IBM® Engineering Requirements Management DOORS vulnerability

An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent transfers if the configurations match. However, two SSH settings were omitted from the configuration check, allowing them to match easily, potentially leading to the reuse of an inappropriate connection.

cURL libcurl could allow a local attacker to bypass security restrictions, caused by a SSH connection too eager reuse still flaw. By sending a specially crafted request, an attacker could exploit this vulnerability to reuse a previously created connection even when an SSH related option had been changed.

— IBM

libcurl would reuse a previously created connection even when an SSH related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, two SSH settings were left out from the configuration match checks, making them match too easily.

— Red Hat