CVE-2023-46848 is a vulnerability identified in Squid version 5.0.3, a widely used caching proxy and web gateway software. The issue stems from an incorrect conversion between numeric types when processing ftp:// URLs either embedded in HTTP request messages or constructed from FTP native input. This flaw can be exploited remotely by an unauthenticated attacker who sends maliciously crafted ftp:// URLs to the vulnerable Squid server. The improper numeric conversion leads to unexpected behavior such as resource exhaustion or application crash, resulting in a Denial of Service (DoS) condition. The vulnerability has a CVSS v3.1 base score of 8.6, indicating high severity, with an attack vector that is network-based, requiring no privileges or user interaction. The scope is complete (S:C), meaning the vulnerability can affect resources beyond the vulnerable component. While no known exploits have been reported in the wild yet, the potential for disruption is significant given Squid's role in managing web traffic and caching. The vulnerability does not impact confidentiality or integrity but severely affects availability, making it a critical concern for organizations relying on Squid for network traffic management. The vulnerability was published on November 3, 2023, and is tracked under CVE-2023-46848. No official patches or mitigations are listed yet, but monitoring vendor advisories and preparing to apply updates is essential.

For European organizations, the primary impact of CVE-2023-46848 is the potential for Denial of Service attacks against Squid proxy servers running version 5.0.3. This can disrupt internet access, internal application connectivity, and caching services, leading to operational downtime and productivity loss. Organizations in sectors such as finance, government, telecommunications, and critical infrastructure that rely heavily on Squid for traffic management and security may experience significant service interruptions. The disruption could also affect compliance with regulatory requirements for service availability and incident response. Since the vulnerability does not compromise data confidentiality or integrity, the risk of data breach is low; however, the availability impact alone can cause cascading effects on business continuity. The lack of authentication or user interaction requirements increases the risk of automated exploitation attempts. European entities with large-scale deployments of Squid proxies, especially those exposed to the internet or handling FTP traffic, are at heightened risk.

1. Monitor official Squid project channels and vendor advisories for patches addressing CVE-2023-46848 and apply updates promptly once available. 2. Until patches are released, consider implementing network-level filtering to block or restrict ftp:// URL traffic to Squid servers, especially from untrusted sources. 3. Review and tighten access controls to limit exposure of Squid proxy servers to the internet or untrusted networks. 4. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect and block malformed ftp:// URL requests targeting this vulnerability. 5. Conduct internal audits to identify all Squid 5.0.3 instances and assess their exposure and criticality. 6. Implement rate limiting or connection throttling on Squid servers to mitigate the impact of potential DoS attempts. 7. Prepare incident response plans to quickly isolate and remediate affected systems in case of exploitation. 8. Consider temporary disabling or restricting FTP proxying features if not essential to reduce attack surface.