CVE-2025-52955 is a vulnerability identified in the routing protocol daemon (rpd) component of Juniper Networks Junos OS, a widely used network operating system in enterprise and service provider environments. The vulnerability stems from an incorrect calculation of buffer size (classified under CWE-131), which leads to memory corruption when specific conditions are met. Specifically, when a logical interface associated with a routing instance experiences continuous flapping, it triggers the transmission of particular updates to the jflow/sflow modules. These updates cause the rpd process to corrupt memory, resulting in a crash and subsequent restart of the daemon. If the updates continue to be received, this leads to a sustained Denial of Service (DoS) condition, effectively disrupting routing operations. The flaw can be exploited by an adjacent unauthenticated attacker, meaning the attacker must have network adjacency but does not require authentication or user interaction to trigger the issue. The affected Junos OS versions include all releases before 21.2R3-S9, all versions of 21.4 and 22.2, versions from 22.4 before 22.4R3-S7, from 23.2 before 23.2R2-S3, from 23.4 before 23.4R2-S4, and from 24.2 before 24.2R2. The CVSS v3.1 base score is 6.5 (medium severity), with an attack vector of adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N, I:N), but high impact on availability (A:H). No known exploits are currently reported in the wild, and no patches are linked in the provided data, indicating that remediation may require vendor updates or configuration changes once available.

For European organizations, especially those relying on Juniper Networks Junos OS for critical routing infrastructure, this vulnerability poses a significant risk to network availability. The ability of an adjacent unauthenticated attacker to cause repeated rpd crashes can lead to persistent routing disruptions, impacting business continuity, service delivery, and potentially causing cascading failures in network-dependent applications. This is particularly critical for sectors such as telecommunications, finance, government, and critical infrastructure operators where network uptime is paramount. The DoS condition could be exploited to degrade or interrupt services, potentially affecting large numbers of users or critical communications. Since the attack requires adjacency, internal network segments or partner networks could be vectors, raising concerns about insider threats or compromised devices within trusted network zones. The lack of impact on confidentiality and integrity limits data breach risks, but the availability impact alone can have severe operational and financial consequences.

Organizations should first inventory their Junos OS deployments to identify affected versions. Until patches are available, network administrators should implement strict network segmentation and access controls to limit adjacency to trusted devices only, reducing the attack surface. Monitoring for unusual interface flapping or abnormal jflow/sflow update patterns can provide early detection of exploitation attempts. Rate limiting or filtering of routing protocol updates at network boundaries may mitigate the risk of sustained DoS conditions. Additionally, applying Juniper's recommended best practices for interface stability and routing instance configuration can reduce the likelihood of triggering the vulnerability. Once Juniper releases patches or updates, prompt testing and deployment are critical. Network operators should also consider deploying redundancy and failover mechanisms to maintain routing availability during potential rpd restarts. Finally, maintaining up-to-date network device logs and integrating them with SIEM solutions can aid in incident response and forensic analysis if exploitation is suspected.