CVE-2024-27354: Computational Denial of Service via Unbounded Primality Testing in phpseclib Vulnerability ID: CVE-2024-27354 CVSS Score: 7.5 Published: 2026-05-06 A computational Denial of Service (DoS) vulnerability in phpseclib allows unauthenticated attackers to exhaust CPU resources by supplying malformed X.509 certificates. The vulnerability arises from missing bit-length upper bounds in the Miller-Rabin primality test implementation when evaluating explicit elliptic curve field parameters. TL;DR phpseclib before versions 1.0.23, 2.0.47, and 3.0.36 suffers from a computational DoS flaw where parsing maliciously crafted X.509 certificates with massive explicit primes triggers an unbounded Miller-Rabin primality test, leading to CPU exhaustion.…