CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS
Percentile
46.4%
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 victimβs session by tossing a valid sessionId
cookie in the victimβs 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.