CVE-2025-46784 is a critical memory management vulnerability identified in Entr'ouvert Lasso version 2.5.1, specifically within the function lasso_node_init_from_message_with_format. This function processes SAML responses, and due to improper release of memory before removing the last reference (CWE-401), a specially crafted SAML response can cause memory depletion. This leads to denial of service conditions by exhausting system memory resources, potentially crashing or severely degrading the availability of services relying on Lasso for SAML authentication. The vulnerability is remotely exploitable over the network without requiring privileges, but it does require the target system to process a malicious SAML response, implying some level of user interaction or automated processing of SAML assertions. The CVSS 3.1 score of 9.6 (AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H) indicates a critical severity with high impact on confidentiality, integrity, and availability, and a wide scope affecting multiple components or systems. No patches or exploits are currently publicly available, but the vulnerability's nature and criticality demand immediate attention. Entr'ouvert Lasso is used in various identity federation and single sign-on (SSO) implementations, making this vulnerability particularly impactful in environments relying on federated identity management.

For European organizations, the impact of CVE-2025-46784 can be significant, especially those relying on Entr'ouvert Lasso for SAML-based authentication in critical applications such as government portals, financial services, healthcare, and large enterprises. Exploitation can lead to denial of service, disrupting authentication services and potentially causing downtime in dependent applications. This can result in operational disruption, loss of user access, and potential cascading effects on business continuity. The vulnerability also poses risks to confidentiality and integrity since malformed SAML responses might be used to manipulate or interfere with authentication flows, although the primary impact is availability. Organizations with high reliance on federated identity and SSO solutions are particularly vulnerable. The lack of known exploits in the wild provides a window for proactive mitigation, but the critical severity necessitates urgent action to prevent potential attacks. Additionally, the cross-domain nature of SAML means that attacks could originate from external identity providers or malicious actors attempting to disrupt federated authentication.

1. Immediate mitigation should focus on upgrading Entr'ouvert Lasso to a patched version once available from the vendor. Since no patch links are currently provided, organizations should monitor vendor advisories closely. 2. Implement strict validation and filtering of incoming SAML responses to detect and block malformed or suspicious assertions before processing. 3. Employ network-level protections such as Web Application Firewalls (WAFs) configured to identify and block anomalous SAML traffic patterns. 4. Limit exposure of SAML endpoints to trusted identity providers and restrict access using IP whitelisting or mutual TLS where feasible. 5. Monitor system memory usage and application logs for unusual spikes or errors related to SAML processing to detect potential exploitation attempts early. 6. Consider deploying rate limiting on SAML response processing to mitigate potential denial of service attempts. 7. Conduct thorough security reviews of federated identity configurations and ensure that all components interacting with Lasso are up to date and securely configured. 8. Prepare incident response plans to quickly address and recover from potential service disruptions caused by exploitation.