Observable Timing Discrepancy Vulnerability in Potatosalad JOSE

CVE-2026-65630

What is CVE-2026-65630?

An observable timing discrepancy vulnerability in the Potatosalad JOSE library allows attackers to exploit the timing of operations during scalar multiplication to recover long-term X25519 private keys. This vulnerability arises due to the implementation of recursive Montgomery ladder operations that depend on the secret private scalar. Since the execution time of various public API entry points can be influenced by the private key, an attacker can submit specially crafted ciphertexts and measure the timing of decryption operations to extract the key bit by bit. This can compromise the confidentiality and authenticity of all data protected by the key, representing a significant security risk for applications utilizing this implementation.

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