CVE-2025-2900 is a high-severity heap-based buffer overflow vulnerability (CWE-122) found in IBM Semeru Runtime versions 8.0.302.0 through 8.0.442.0, 11.0.12.0 through 11.0.26.0, 17.0.0.0 through 17.0.14.0, and 21.0.0.0 through 12.0.6.0. The flaw originates from a defect in the native AES/CBC encryption implementation within the runtime environment. Specifically, the vulnerability arises when the runtime processes AES encryption or decryption operations using the Cipher Block Chaining (CBC) mode, leading to a heap-based buffer overflow. This overflow can cause the affected process to crash, resulting in a denial of service (DoS). The vulnerability does not impact confidentiality or integrity directly but severely affects availability by crashing the runtime environment. The CVSS v3.1 score is 7.5 (high), reflecting that the vulnerability can be exploited remotely (AV:N) without any privileges (PR:N) or user interaction (UI:N). The scope is unchanged (S:U), and the impact is limited to availability (A:H) with no confidentiality or integrity loss. No known exploits are currently in the wild, and no patches have been linked yet, indicating that mitigation may require vendor updates once available. IBM Semeru Runtime is a Java runtime distribution, widely used in enterprise environments for running Java applications. The heap-based buffer overflow in the encryption module is critical because it can be triggered remotely without authentication, potentially allowing attackers to disrupt services dependent on the runtime, including web applications, middleware, and backend services.

For European organizations, the impact of CVE-2025-2900 can be significant, especially for those relying on IBM Semeru Runtime to run critical Java applications. The denial of service caused by the buffer overflow can lead to unexpected application crashes, service downtime, and disruption of business operations. This is particularly critical for sectors such as finance, healthcare, telecommunications, and government services where high availability and reliability are mandatory. The runtime's failure could cascade into broader system outages or impact dependent services, causing operational delays and potential financial losses. Additionally, the lack of confidentiality or integrity impact means data breaches are unlikely, but service disruption alone can damage reputation and compliance with regulations like GDPR, which mandates service availability and incident reporting. The vulnerability's remote exploitability without authentication increases the risk profile, as attackers can trigger the DoS from anywhere, potentially as part of a larger attack campaign targeting European infrastructure or enterprises.

European organizations should immediately inventory their environments to identify all instances of IBM Semeru Runtime within the affected version ranges. Until a vendor patch is released, organizations should consider the following mitigations: 1) Implement network-level protections such as Web Application Firewalls (WAFs) and Intrusion Prevention Systems (IPS) to detect and block anomalous traffic patterns that may exploit AES/CBC operations. 2) Restrict network access to critical Java applications running on Semeru Runtime to trusted IP ranges and enforce strict segmentation to limit exposure. 3) Monitor application logs and runtime behavior for signs of crashes or abnormal terminations that may indicate exploitation attempts. 4) Engage with IBM support channels to obtain early patches or workarounds as they become available. 5) Where feasible, temporarily migrate critical workloads to alternative Java runtime environments not affected by this vulnerability. 6) Conduct thorough testing of updates in staging environments before deployment to production to avoid service disruption. 7) Maintain robust incident response plans to quickly address potential DoS incidents stemming from this vulnerability.