# CVE-2021-41171: Bypass bruteforce protection on login form in elabftw

> Attackers can bypass brute-force login protection in eLabFTW by using forged PHPSESSID values, facilitating password guessing attacks.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-q67h-5pc3-g6jv

## What is CVE-2021-41171?

CVE-2021-41171 is a medium-severity vulnerability in elabftw, published on 22 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

eLabFTW is an open source electronic lab notebook manager for research teams. In versions of eLabFTW before 4.1.0, it allows attackers to bypass a brute-force protection mechanism by using many different forged PHPSESSID values in HTTP Cookie header. This issue has been addressed by implementing brute force login protection, as recommended by Owasp with Device Cookies. This mechanism will not impact users and will effectively thwart any brute-force attempts at guessing passwords. The only correct way to address this is to upgrade to version 4.1.0. Adding rate limitation upstream of the eLabFTW service is of course a valid option, with or without upgrading.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2021-41171?

It affects 1 product.


Products: Elabftw Elabftw.

## How do I fix CVE-2021-41171?

No fix has been published for CVE-2021-41171 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-41171 being exploited?

There is no known exploitation of CVE-2021-41171 in the wild and no public exploit code.

## Other vulnerabilities in elabftw

- [CVE-2021-43834](https://insights.sbomify.com/CVE-2021-43834/): Incorrect Authentication in elabftw (critical 9.1)
- [CVE-2024-28100](https://insights.sbomify.com/CVE-2024-28100/): Stored Cross-site Scripting leading to arbitrary actions taken on behalf of users in elabftw (high 8.9)
- [CVE-2019-12185](https://insights.sbomify.com/CVE-2019-12185/): File upload in n/a (high 8.8)
- [CVE-2024-25632](https://insights.sbomify.com/CVE-2024-25632/): Unauthorised granting of administrator privileges over arbitrary teams under certain circumstances (high 8.6)
- [CVE-2025-25206](https://insights.sbomify.com/CVE-2025-25206/): Incorrect input validation could allow an authenticated user to read sensitive information (high 8.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41171 and fix it if it is affected.

What it is: CVE-2021-41171 is a medium-severity vulnerability in elabftw, published on 22 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-41171 in the wild and no public exploit code.

Affected product: elabftw. 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-2021-41171/ (Markdown: https://insights.sbomify.com/CVE-2021-41171/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41171
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41171
- OSV: https://osv.dev/vulnerability/CVE-2021-41171

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41171/
Summaries are generated and may contain mistakes; the official description above is the record.