# CVE-2026-42210: Webmin 2FA requirement bypass

> Attackers can bypass two-factor authentication in Webmin using Basic authentication if they know the username and password.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Jul 2026
- **Updated:** 20 Jul 2026
- **Also known as:** GHSA-qpww-fff2-6fgv

## What is CVE-2026-42210?

CVE-2026-42210 is a medium-severity authentication bypass vulnerability in webmin, published on 20 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Webmin is a web-based system administration tool for Unix-like servers. Prior to version 2.640, for Webmin accounts that require a second authentication factor (typically TOTP), an attacker with knowledge of the username and password can bypass the 2FA requirement by using Basic authentication. Webmin is a web-based system administration tool for Unix-like servers. As a workaround, apply the patch from commit da18a16c84ae5c0b78cad79609cb0efb174000ec manually.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-42210?


## How do I fix CVE-2026-42210?

No fix has been published for CVE-2026-42210 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42210 being exploited?

There is no known exploitation of CVE-2026-42210 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42210 and fix it if it is affected.

What it is: CVE-2026-42210 is a medium-severity authentication bypass vulnerability in webmin, published on 20 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-42210 in the wild and no public exploit code.

Affected product: webmin. 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-2026-42210/ (Markdown: https://insights.sbomify.com/CVE-2026-42210/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42210
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42210
- OSV: https://osv.dev/vulnerability/CVE-2026-42210

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42210/
Summaries are generated and may contain mistakes; the official description above is the record.