CVE-2025-46705 in Lasso
Summary
by MITRE • 11/05/2025
A denial of service vulnerability exists in the g_assert_not_reached functionality of Entr'ouvert Lasso 2.5.1 and 2.8.2. A specially crafted SAML assertion response can lead to a denial of service. An attacker can send a malformed SAML response to trigger this vulnerability.
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Analysis
by VulDB Data Team • 11/08/2025
The vulnerability identified as CVE-2025-46705 represents a critical denial of service weakness within the Entr'ouvert Lasso 2.5.1 and 2.8.2 software implementations. This issue specifically targets the g_assert_not_reached functionality, which serves as a debugging mechanism designed to detect unreachable code paths during software execution. The flaw manifests when the system processes malformed SAML assertion responses, causing the application to crash or become unresponsive. The attack vector is particularly concerning as it requires minimal privileges and can be executed through standard network communication channels, making it accessible to a broad range of potential threat actors.
The technical implementation of this vulnerability stems from insufficient input validation within the SAML processing pipeline of the Lasso software. When a malformed SAML assertion response is received, the g_assert_not_reached function fails to properly handle the unexpected input, leading to an abrupt termination of the application process. This behavior aligns with CWE-476 which describes NULL pointer dereferences, though in this case the issue manifests as an assertion failure rather than a direct pointer dereference. The flaw essentially bypasses normal error handling procedures, causing the application to terminate unexpectedly rather than gracefully managing the malformed data.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially be leveraged for more sophisticated attacks within a broader threat landscape. When an attacker successfully triggers this denial of service condition, they effectively prevent legitimate users from accessing the authentication services that rely on the vulnerable Lasso implementation. This can cascade into broader system availability issues, particularly in environments where single sign-on functionality is critical for enterprise operations. The vulnerability also aligns with ATT&CK technique T1499 which covers network denial of service attacks, though this particular instance represents an application-level rather than network-level disruption.
Organizations utilizing Entr'ouvert Lasso versions 2.5.1 and 2.8.2 should implement immediate mitigations to protect against exploitation of this vulnerability. The primary recommendation involves applying the vendor-provided security patches or updates that address the specific assertion handling logic. Additionally, implementing network-level controls such as intrusion detection systems can help detect and block malformed SAML responses before they reach vulnerable systems. Input validation measures should be strengthened at multiple layers including application firewalls and API gateways to prevent malformed data from reaching the core authentication processing components. Security monitoring should include detection of unusual application termination patterns and service disruption events that may indicate exploitation attempts. The vulnerability demonstrates the importance of robust error handling in security-critical applications and highlights the need for comprehensive testing of edge cases in authentication protocols.