CSRF token fixation in fastify-passportGHSA-2ccf-ffrj-m4qw
MEDIUMFix: fastify/fastify-passport@07c90feGHSA-2ccf-ffrj-m4qw is a medium-severity (CVSS 6.5) Cross-Site Request Forgery (CSRF) vulnerability in @fastify/passport. A fix is available for @fastify/passport — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-2ccf-ffrj-m4qw.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@fastify/passportnpmDescription
The CSRF protection enforced by the @fastify/csrf-protection library, when combined with @fastify/passport, can be bypassed by network and same-site attackers.
Details
fastify/csrf-protection implements the synchronizer token pattern (using plugins @fastify/session and @fastify/secure-session) by storing a random value used for CSRF token generation in the _csrf attribute of a user's session.
The @fastify/passport library does not clear the session object upon authentication, preserving the _csrf attribute between pre-login and authenticated sessions. Consequently, CSRF tokens generated before authentication are still valid. Network and same-site attackers can thus obtain a CSRF token for their pre-session, fixate that pre-session in the victim's browser via cookie tossing, and then perform a CSRF attack after the victim authenticates.
Fix
As a solution, newer versions of @fastify/passport include the configuration options
clearSessionOnLogin (default: true)andclearSessionIgnoreFields (default: ['session'])
to clear all the session attributes by default, preserving those explicitly defined in clearSessionIgnoreFields.
Credits
- Pedro Adão (@pedromigueladao), Instituto Superior Técnico, University of Lisbon
- Marco Squarcina (@lavish), Security & Privacy Research Unit, TU Wien
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @fastify/passport | all versions | 1.1.0npm install @fastify/passport@1.1.0 |
| 📦npm | @fastify/passport | ≥ 2.0.0&&< 2.3.0 | 2.3.0npm install @fastify/passport@2.3.0 |
Affected Products
passportfastifyDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @fastify/passport, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @fastify/passport to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2ccf-ffrj-m4qw is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is GHSA-2ccf-ffrj-m4qw in your dependencies?
Find it across npm, including transitive dependencies.