CVE-2026-56022
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedWebmin 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceWebmin contains an authentication bypass where the application accepts basic authentication without requiring session cookies when the request includes a 'User-Agent: webmin' header. This allows attackers to bypass configured MFA requirements by simply adding this specific User-Agent string to their requests.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 2.640CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify if Webmin is installed and runningCheck for webmin processes (ps aux | grep webmin) or listening on common webmin ports (10000/tcp)Affected if Webmin is found running on the system
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Determine installed Webmin versionCheck /etc/webmin/version or access the Webmin UI and view the version informationAffected if Version is below 2.641
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Verify if MFA is configuredCheck Webmin authentication settings via Webmin UI under 'Webmin Configuration' > 'Authentication' or inspect /etc/webmin/miniserv.conf for mfa=1 settingAffected if MFA is enabled in the Webmin configuration
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Test User-Agent header authentication behaviorSend a basic auth request with 'User-Agent: webmin' header to the Webmin endpoint (e.g., curl -u username:password -A 'webmin' https://target:10000/) and observe if authentication succeeds without a session cookieAffected if Authentication succeeds with only User-Agent: webmin and basic credentials, bypassing session cookie requirements
The environment is affected if Webmin version is below 2.641 and the system accepts authentication with just a 'User-Agent: webmin' header plus basic credentials, bypassing the normal session cookie and potentially MFA requirements.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped2.640
Upgrade Webmin to version 2.641 or later. After upgrading, verify that MFA enforcement is working correctly and that the authentication flow properly requires session cookies regardless of User-Agent.
2.641
- Upgrade Webmin to version 2.641 or later to remediate this vulnerability
- After upgrading, verify that MFA requirements are properly enforced for all authentication methods
- Confirm that the 'User-Agent: webmin' header no longer bypasses session cookie requirements
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-56022 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-56022 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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