Top 10 winner

Psychic Signatures in Java

CVE-2022-21449: Psychic Signatures in Java

@neilmaddog · Neil Madden · 19 April 2022

The Java 15 rewrite of ECDSA verification from C++ into Java dropped the check that signature values r and s are non-zero, so an all-zero signature verifies against any message and any public key. On Java 15 to 18 that forges TLS handshakes, signed JWTs, SAML assertions, OIDC id tokens and WebAuthn assertions (CVE-2022-21449).

Record

Document

CVE-2022-21449: Psychic Signatures in Java

Researcher

@neilmaddog

Published by

Neil Madden

Date

19 April 2022

Topic

Server

In the archive

• Ranked #8 in the 2022 Top 10 Web Hacking Techniques

Tags

• auth-bypass
• jwt
• webauthn
• saml
• openid
• tls
• java
• cve
• owasp-a01-2021
• owasp-a02-2021
• owasp-a07-2021

This page is the archive's own catalogue record. The research is the work of @neilmaddog, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on 10 August 2026.