CVE-2026-49265 OAuthLib: Timing Attack Vulnerability in PKCE code_verifier Comparison

OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. From 3.0.0 until 4.0.0, OAuthLib's PKCE checks in oauthlib/oauth2/rfc6749/granttypes/authorizationcode.py compare attacker-supplied codeverifier values with stored challenges using ordinary string equality in...