CVE-2021-38195

CVE-2021-38195 is a critical vulnerability affecting the libsecp256k1 Rust crate, specifically versions prior to 0.5.0, used by products like parity libsecp256k1. This flaw allows for the verification of invalid signatures due to an overflow where the R or S parameter can exceed the curve order. With a CVSS score of 9.8 (CRITICAL), it presents a severe risk, allowing unauthenticated attackers to achieve high confidentiality, integrity, and availability impacts over the network with low attack complexity. While there is no evidence of active exploitation, nor publicly available exploit code in Metasploit, Nuclei, or ExploitDB, the vulnerability has garnered significant community attention with 10 mentions, indicating awareness among security researchers.