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.NET
.NET NuGet
Not in CISA KEV
LOW severity

CVE-2023-49274 — Umbraco.CMS

LOW

CVE-2023-49274 is a low-severity (CVSS 3.7) Information Exposure vulnerability in Umbraco.CMS. A fix is available for Umbraco.CMS — see the affected versions and patch details below.

Umbraco CMS SMTP misconfiguration exposes potential registered user email

Also known asGHSA-8qp8-9rpw-j46c
Published
Updated
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed
Exploitation data as of Nov 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs40th percentile — riskier than 40% of all scored CVEsHighest risk
0.00%0.32%0.64%0.96%0.4%0.5%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected
.NETUmbraco.CMS.NETUmbraco.CMS.NETUmbraco.CMS

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Impact

A user enumeration attack is possible when SMTP is not setup correctly, but reset password is enabled

Explanation of the vulnerability

Two different error messages was shown, based on if the user exists or not when using the forgot password functionality, when the SMTP was configured but do not response.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetUmbraco.CMS≥ 8.0.0&&< 8.18.108.18.10dotnet add package Umbraco.CMS --version 8.18.10
.NETNuGetUmbraco.CMS≥ 9.0.0&&< 10.8.110.8.1dotnet add package Umbraco.CMS --version 10.8.1
.NETNuGetUmbraco.CMS≥ 11.0.0&&< 12.3.412.3.4dotnet add package Umbraco.CMS --version 12.3.4

Affected Products

1 product · 3 configurations
Application
umbraco cmsumbraco
≥ 12.0.0 && < 12.3.4
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Umbraco.CMS, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update Umbraco.CMS to 8.18.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49274 is resolved across your whole dependency graph.

  3. Workarounds

    Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

#### Impact A user enumeration attack is possible when SMTP is not setup correctly, but reset password is enabled #### Explanation of the vulnerability Two different error messages was shown, based on if the user exists or not when using the forgot password functionality, when the SMTP was configured but do not response.
O3 Security · Impact-Aware SCA

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CVE-2023-49274: Umbraco.CMS — Fixed in 8.18.10