# CVE-2021-43834: Incorrect Authentication in elabftw

> Attackers can authenticate as existing users in eLabFTW if LDAP or SAML is enabled, allowing unauthorized account access.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 15 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-98rp-gx76-33ph

## What is CVE-2021-43834?

CVE-2021-43834 is a critical authentication bypass vulnerability in elabftw, published on 15 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

eLabFTW is an electronic lab notebook manager for research teams. In versions prior to 4.2.0 there is a vulnerability which allows an attacker to authenticate as an existing user, if that user was created using a single sign-on authentication option such as LDAP or SAML. It impacts instances where LDAP or SAML is used for authentication instead of the (default) local password mechanism. Users should upgrade to at least version 4.2.0.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-43834?

It affects 1 product.


Products: Elabftw Elabftw.

## How do I fix CVE-2021-43834?

No fix has been published for CVE-2021-43834 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-43834 being exploited?

There is no known exploitation of CVE-2021-43834 in the wild and no public exploit code.

## Other vulnerabilities in elabftw

- [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)
- [CVE-2021-43833](https://insights.sbomify.com/CVE-2021-43833/): Account takeover in eLabFTW (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-43834 and fix it if it is affected.

What it is: CVE-2021-43834 is a critical authentication bypass vulnerability in elabftw, published on 15 Dec 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-2021-43834 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-2021-43834/ (Markdown: https://insights.sbomify.com/CVE-2021-43834/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43834
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43834
- OSV: https://osv.dev/vulnerability/CVE-2021-43834

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43834/
Summaries are generated and may contain mistakes; the official description above is the record.