CVE-2020-24613: 
NixOS vulnerability analysis and mitigation

wolfSSL before version 4.5.0 contains a critical vulnerability (CVE-2020-24613) in its TLS 1.3 client implementation. The vulnerability involves mishandling of TLS 1.3 server data in the WAIT_CERT_CR state within SanityCheckTls13MsgReceived() function in tls13.c. This represents an incorrect implementation of the TLS 1.3 client state machine (NVD).

The vulnerability exists in the TLS 1.3 client state machine implementation, specifically within the SanityCheckTls13MsgReceived() function in tls13.c. The issue manifests when handling server data in the WAIT_CERT_CR state. The vulnerability has been assigned a CVSS v3.1 base score of 6.8 (MEDIUM) with the vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N (NVD).

The vulnerability allows attackers in a privileged network position to completely impersonate any TLS 1.3 servers. This enables them to read or modify potentially sensitive information between clients using the wolfSSL library and these TLS servers (NVD).

The vulnerability requires an attacker to be in a privileged network position to exploit. It affects the TLS 1.3 client communication which is used for secure communications. The vulnerability has been confirmed to be exploitable in real-world scenarios (Azure Sphere).

The vulnerability has been fixed in wolfSSL version 4.5.0. Users are strongly recommended to upgrade to this version or later to address the security issue. No alternative workarounds have been publicly documented (NVD).

Microsoft acknowledged the severity of this vulnerability by incorporating the fix in their Azure Sphere OS version 20.08 release, describing it as a critical security patch that directly impacts TLS 1.3 client communication (Azure Sphere).