# CVE-2023-29020: Cross site request forgery token fixation in fastify-passport

> Attackers can bypass CSRF protection in fastify-passport by fixing session tokens, allowing unauthorized actions after victim authentication.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Apr 2023
- **Updated:** 4 Feb 2025
- **Also known as:** GHSA-2ccf-ffrj-m4qw

## What is CVE-2023-29020?

CVE-2023-29020 is a medium-severity vulnerability in fastify-passport, published on 21 Apr 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

@fastify/passport is a port of passport authentication library for the Fastify ecosystem. The CSRF (Cross-Site Request Forger) protection enforced by the `@fastify/csrf-protection` library, when combined with `@fastify/passport` in affected versions, can be bypassed by network and same-site attackers. `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. As a solution, newer versions of `@fastify/passport` include the configuration options: `clearSessionOnLogin (default: true)` and `clearSessionIgnoreFields (default: ['passport', 'session'])` to clear all the session attributes by default, preserving those explicitly defined in `clearSessionIgnoreFields`.

Weakness: CWE-384 (Session Fixation), CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2023-29020?

4 open source packages ship an affected version, including @fastify/passport. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@fastify/passport` | npm | All versions | 1.1.0 |
| `@fastify/passport` | npm | All versions | 1.1.0 |
| `@fastify/passport` | npm | From 2.0.0 | 2.3.0 |
| `@fastify/passport` | npm | From 2.0.0 | 2.3.0 |

Products: Fastify Passport.

## How do I fix CVE-2023-29020?

Upgrade @fastify/passport to a fixed version for your release line: 1.1.0 or 2.3.0.

## Is CVE-2023-29020 being exploited?

There is no known exploitation of CVE-2023-29020 in the wild and no public exploit code.

## Other vulnerabilities in fastify-passport

- [CVE-2023-29019](https://insights.sbomify.com/CVE-2023-29019/): Session fixation in fastify-passport (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-29020 and fix it if it is affected.

What it is: CVE-2023-29020 is a medium-severity vulnerability in fastify-passport, published on 21 Apr 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-29020 in the wild and no public exploit code.

Affected packages and fixed versions:
- @fastify/passport (npm): affected all versions; fixed in 1.1.0
- @fastify/passport (npm): affected all versions; fixed in 1.1.0
- @fastify/passport (npm): affected from 2.0.0; fixed in 2.3.0
- @fastify/passport (npm): affected from 2.0.0; fixed in 2.3.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-29020/ (Markdown: https://insights.sbomify.com/CVE-2023-29020/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-29020
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-29020
- OSV: https://osv.dev/vulnerability/CVE-2023-29020

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-29020/
Summaries are generated and may contain mistakes; the official description above is the record.