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Umbraco CmsApplication · Umbraco

CVE-2023-49274

MEDIUM · 5.3 CVSS v3.1 Published 2023-12-12
Fix available
A fix is available. Upgrade to 8.18.10 / 10.8.1 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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 · unedited
Umbraco is an ASP.NET content management system (CMS). Starting in version 8.0.0 and prior to versions 8.18.10, 10.8.1, and 12.3.4, a user enumeration attack is possible when SMTP is not set up correctly, but reset password is enabled. Versions 8.18.10, 10.8.1, and 12.3.4 contain a patch for this issue.

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 confidence

In affected Umbraco versions (8.0.0 through before 8.18.10, 10.8.1, and 12.3.4), when the password reset feature is enabled but SMTP is not properly configured, the application returns distinguishable responses for valid vs. invalid usernames, allowing an attacker to enumerate valid user accounts through the password reset functionality.

MitigationUpgrade Umbraco to version 8.18.10, 10.8.1, or 12.3.4 or later, and ensure SMTP is properly configured so that password reset operations execute correctly without leaking user existence information.

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
Umbraco CmsApplication
Affected:>= 8.0.0, < 8.18.10>= 10.0.0, < 10.8.1>= 12.0.0, < 12.3.4

CVSS 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
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Umbraco version
    Locate the Umbraco Core DLL or check the version in the /bin folder, or query the /umbraco/api/ServerStatus endpoint if accessible, or review the installed package version in the backoffice 'Packages' section
    Affected if The version falls within 8.0.0 to < 8.18.10, 10.0.0 to < 10.8.1, or 12.0.0 to < 12.3.4
  2. Confirm password reset is enabled
    Examine the membership provider configuration in web.config (for v8) or appsettings.json (for v10/v12) - look for allowPasswordReset='true' or 'PasswordReset' settings in the security section
    Affected if Password reset functionality is enabled in the Umbraco configuration
  3. Verify SMTP configuration status
    Inspect appsettings.json (v10/v12) or web.config (v8) for the 'Smtp' section and confirm whether valid host, port, and credentials are defined
    Affected if SMTP is not configured or is misconfigured such that email delivery would fail
  4. Test password reset endpoint response differentiation
    Submit two password reset requests to /umbraco/api/ForgotPassword (or equivalent endpoint) using a known-invalid username versus a potentially valid username and compare the HTTP response messages
    Affected if The application returns distinctly different responses indicating user existence versus non-existence

You are affected if your Umbraco version is in the vulnerable range AND password reset is enabled AND SMTP is not properly configured, allowing an attacker to distinguish valid from invalid usernames via password reset responses.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 8.18.10 / 10.8.1 / 12.3.4 or later
Fixed in 8.18.1010.8.112.3.4
Interim mitigation

Upgrade Umbraco to version 8.18.10, 10.8.1, or 12.3.4 or later, and ensure SMTP is properly configured so that password reset operations execute correctly without leaking user existence information.

Recommended fix High confidence

Umbraco 8.18.10 / 10.8.1 / 12.3.4 (depending on your branch)

  1. Identify your current Umbraco version by checking the project files or administration dashboard
  2. For Umbraco 8.x: Upgrade to version 8.18.10 or later
  3. For Umbraco 10.x: Upgrade to version 10.8.1 or later
  4. For Umbraco 12.x: Upgrade to version 12.3.4 or later
  5. After upgrading, verify that SMTP is properly configured in the Umbraco backoffice under Settings > Messaging > Emails
  6. Test the password reset functionality to confirm the user enumeration vulnerability is remediated
Caveat Standard minor version upgrade; review Umbraco release notes for any configuration or API changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Umbraco Cms Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-49274 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data