title: Session fixation in fastify-passport
description: @fastify/passport is a port of passport authentication library for the Fastify ecosystem. Applications using `@fastify/passport` in affected versions 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. Users are advised to upgrade. There are no known workarounds for this vulnerability.
problem types: CWE-384: Session Fixation
affected:
{
vendor: fastify
product: fastify-passport
versions:
version: < 1.1.0, status: affected
version: >= 2.0.0, < 2.3.0, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 8.1
baseSeverity: HIGH
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: REQUIRED
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
version: 3.1
]