Applications using @fastify/passport for user authentication, in combination with @fastify/session as the underlying session management mechanism, are vulnerable to session fixation attacks from network and same-site attackers.
fastify applications rely on the @fastify/passport library for user authentication. The login and user validation are performed by the authenticate function. When executing this function, the sessionId is preserved between the pre-login and the authenticated session. Network and same-site attackers can hijack the victim's session by tossing a valid sessionId cookie in the victim's browser and waiting for the victim to log in on the website.
As a solution, newer versions of @fastify/passport regenerate sessionId upon login, preventing the attacker-controlled pre-session cookie from being upgraded to an authenticated session.
{
"nvd_published_at": "2023-04-21T23:15:20Z",
"severity": "HIGH",
"github_reviewed_at": "2023-04-21T22:33:30Z",
"github_reviewed": true,
"cwe_ids": [
"CWE-384"
]
}