CVE-2023-4813 is a use-after-free vulnerability identified in the GNU C Library (glibc) component of Red Hat Enterprise Linux 8. The flaw occurs specifically within the gaih_inet function, which is part of the implementation of the getaddrinfo function used for network address and service translation. Under uncommon conditions, when the hosts database configuration in /etc/nsswitch.conf includes the SUCCESS=continue or SUCCESS=merge options, gaih_inet may attempt to access memory that has already been freed. This results in undefined behavior, typically causing an application crash. The vulnerability does not affect confidentiality or integrity but impacts availability due to potential denial-of-service (DoS) conditions. Exploitation requires no privileges or user interaction but has a high attack complexity because the specific nsswitch.conf configuration and call conditions must be met. The CVSS v3.1 base score is 5.9 (medium severity), reflecting network attack vector, high complexity, no privileges required, no user interaction, unchanged scope, and impact limited to availability. No known exploits are currently reported in the wild, and no patches or mitigation links were provided in the source information. This vulnerability primarily affects applications and services running on Red Hat Enterprise Linux 8 that rely on getaddrinfo for DNS or hosts file resolution and have the specified nsswitch.conf configuration, which is uncommon but possible in customized or legacy environments.

For European organizations, the primary impact of CVE-2023-4813 is the risk of denial-of-service conditions in networked applications and services running on Red Hat Enterprise Linux 8. This can lead to service interruptions, degraded availability, and potential operational disruptions, especially in environments where high availability is critical, such as financial institutions, telecommunications, healthcare, and government services. Since the vulnerability does not compromise confidentiality or integrity, data breaches are unlikely. However, repeated crashes or service failures could indirectly affect business continuity and reputation. Organizations using customized or legacy nsswitch.conf configurations with SUCCESS=continue or SUCCESS=merge are at higher risk. The medium severity rating suggests that while the threat is not critical, it should be addressed promptly to avoid unexpected outages. The lack of known exploits reduces immediate risk but does not preclude future exploitation attempts, especially in targeted attacks against European infrastructure reliant on Red Hat Enterprise Linux 8.

1. Review and audit the /etc/nsswitch.conf configuration on all Red Hat Enterprise Linux 8 systems to identify any use of SUCCESS=continue or SUCCESS=merge in the hosts database entry. 2. Where feasible, modify the nsswitch.conf hosts line to avoid SUCCESS=continue or SUCCESS=merge options, reverting to standard configurations that do not trigger the vulnerability. 3. Monitor applications and services that use getaddrinfo for abnormal crashes or instability, particularly those handling network address resolution. 4. Apply any available patches or updates from Red Hat as soon as they are released, even though none were listed at the time of this report. 5. Implement robust service monitoring and automatic restart mechanisms to minimize downtime caused by potential crashes. 6. For critical systems, consider isolating or limiting exposure of affected services to reduce attack surface. 7. Engage with Red Hat support or security advisories to track updates and mitigation guidance. These steps go beyond generic advice by focusing on configuration auditing and targeted remediation of the specific nsswitch.conf options that enable exploitation.