CVE-2022-25638: 
NixOS vulnerability analysis and mitigation

In wolfSSL before 5.2.0, a certificate validation bypass vulnerability (CVE-2022-25638) was discovered that affects TLS 1.3 client authentication to a TLS 1.3 server. The vulnerability occurs when the sigalgo field differs between the certificateverify message and the certificate message (WolfSSL Security, NVD).

The vulnerability is related to certificate validation during TLS 1.3 mutual authentication. The issue arises specifically when there is a mismatch between the signature algorithm (sigalgo) specified in the certificateverify message and the one in the certificate message. This mismatch could lead to improper certificate validation, potentially allowing authentication bypass (WolfSSL PR). The vulnerability has been assigned a CVSS v3.1 base score of 6.5 (Medium) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N (NVD).

The vulnerability could allow an attacker to bypass certificate validation during TLS 1.3 client authentication to a TLS 1.3 server. This could potentially lead to authentication bypass, allowing unauthorized access to protected resources (WolfSSL Security).

The vulnerability was fixed in wolfSSL version 5.2.0. Users are recommended to upgrade to this version or later to address the issue. The fix involves proper validation of signature algorithms between certificate_verify and certificate messages (WolfSSL PR).

The vulnerability was discovered and reported by Aina Toky Rasoamanana and Olivier Levillain of Télécom SudParis (WolfSSL Security). Microsoft acknowledged the vulnerability and included fixes in their Azure Sphere OS version 22.04 update (Azure Update).