CVE-2025-59362 is a high-severity vulnerability affecting Squid proxy server versions up to 7.1. The issue arises from improper handling of ASN.1 encoding for long SNMP Object Identifiers (OIDs) within the function asn_build_objid located in lib/snmplib/asn1.c. ASN.1 (Abstract Syntax Notation One) is a standard interface description language used for defining data structures that can be serialized and deserialized in a cross-platform way, commonly used in SNMP (Simple Network Management Protocol) communications. The vulnerability is classified under CWE-172, which relates to the improper handling of data types or encoding, potentially leading to memory corruption or logic errors. The CVSS v3.1 base score is 8.2, indicating a high severity level. The vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N indicates that the vulnerability is remotely exploitable over the network without authentication or user interaction, with low attack complexity. The impact on confidentiality is low, but integrity impact is high, and availability is not affected. This suggests that an attacker could manipulate or corrupt data processed by the SNMP handling routines in Squid, potentially leading to unauthorized modification or injection of data, but not causing denial of service. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability affects the core SNMP library used by Squid, which is a widely deployed caching and forwarding HTTP proxy server. Exploitation could allow remote attackers to compromise the integrity of SNMP data processing, possibly enabling further attacks or unauthorized control over SNMP-managed devices or services integrated with Squid.

For European organizations, the impact of CVE-2025-59362 can be significant, especially for those relying on Squid proxy servers in their network infrastructure. Squid is commonly used in enterprise environments for web caching, access control, and traffic filtering. The vulnerability's ability to be exploited remotely without authentication means attackers can potentially manipulate SNMP data or proxy behavior, leading to data integrity breaches. This could affect monitoring systems, network management, and security controls that depend on SNMP data integrity. In sectors such as finance, telecommunications, government, and critical infrastructure, where SNMP is used for device management and monitoring, this vulnerability could undermine trust in network telemetry and control systems. Additionally, compromised SNMP data could be leveraged to pivot attacks or inject malicious configurations, increasing the risk of broader network compromise. The lack of impact on availability reduces the likelihood of immediate service disruption, but the integrity compromise poses a stealthy threat that could persist undetected.

Organizations should prioritize the following mitigation steps: 1) Monitor official Squid project communications and security advisories for patches addressing CVE-2025-59362 and apply them promptly once available. 2) Temporarily disable or restrict SNMP functionality within Squid if feasible, especially if SNMP is not critical to current operations. 3) Implement network-level controls to limit access to Squid servers from untrusted or external networks, using firewalls and segmentation to reduce exposure. 4) Employ SNMPv3 with strong authentication and encryption where SNMP usage is necessary, to mitigate risks from manipulated SNMP data. 5) Conduct thorough logging and monitoring of SNMP-related traffic and Squid proxy logs to detect anomalous or suspicious activity indicative of exploitation attempts. 6) Review and harden SNMP configurations on all managed devices and proxies to minimize attack surface. 7) Consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of identifying malformed ASN.1 or SNMP traffic anomalies. These targeted measures go beyond generic patching advice and focus on reducing attack vectors and improving detection capabilities.