# CVE-2021-3740: Session Fixation in chatwoot/chatwoot

> Attackers can maintain unauthorized access via old session tokens after a user changes their password, requiring an upgrade to Chatwoot.

- **Severity:** Medium 6.8 (`CVSS:3.0/AV:A/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 15 Nov 2024
- **Updated:** 15 Nov 2024
- **Also known as:** GHSA-7c75-4mxr-f248

## What is CVE-2021-3740?

CVE-2021-3740 is a medium-severity authentication bypass vulnerability in chatwoot/chatwoot, published on 15 Nov 2024. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A Session Fixation vulnerability exists in chatwoot/chatwoot versions prior to 2.4.0. The application does not invalidate existing sessions on other devices when a user changes their password, allowing old sessions to persist. This can lead to unauthorized access if an attacker has obtained a session token.

Weakness: CWE-384 (Session Fixation)

## Which versions are affected by CVE-2021-3740?

It affects 1 product.


Products: Chatwoot Chatwoot.

## How do I fix CVE-2021-3740?

No fix has been published for CVE-2021-3740 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3740 being exploited?

There is no known exploitation of CVE-2021-3740 in the wild and no public exploit code.

## Other vulnerabilities in chatwoot/chatwoot

- [CVE-2022-3741](https://insights.sbomify.com/CVE-2022-3741/): Improper Restriction of Excessive Authentication Attempts in chatwoot/chatwoot (critical 9.4)
- [CVE-2025-21628](https://insights.sbomify.com/CVE-2025-21628/): Chatwoot has a Blind SQL-injection in Conversation and Contacts filters (critical 9.1)
- [CVE-2022-0542](https://insights.sbomify.com/CVE-2022-0542/): Cross-site Scripting (XSS) - DOM in chatwoot/chatwoot (high 8.8)
- [CVE-2022-1022](https://insights.sbomify.com/CVE-2022-1022/): Cross-site Scripting (XSS) - Stored in chatwoot/chatwoot (high 8.1)
- [CVE-2021-3742](https://insights.sbomify.com/CVE-2021-3742/): Server-Side Request Forgery (SSRF) in chatwoot/chatwoot (high 7.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3740 and fix it if it is affected.

What it is: CVE-2021-3740 is a medium-severity authentication bypass vulnerability in chatwoot/chatwoot, published on 15 Nov 2024. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-3740 in the wild and no public exploit code.

Affected product: chatwoot/chatwoot. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2021-3740/ (Markdown: https://insights.sbomify.com/CVE-2021-3740/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3740
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3740
- OSV: https://osv.dev/vulnerability/CVE-2021-3740

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3740/
Summaries are generated and may contain mistakes; the official description above is the record.