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.NET
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Not in CISA KEV
MEDIUM severity

CVE-2019-1010199 — ServiceStack

MEDIUMFix: ServiceStack/ServiceStack@a0e0d7d

CVE-2019-1010199 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in ServiceStack. A fix is available for ServiceStack — see the affected versions and patch details below.

Cross site scripting attack in ServiceStack Framework

Also known asGHSA-vcfc-9wcp-j623
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs60th percentile — riskier than 60% of all scored CVEsHighest risk
0.00%0.46%0.93%1.39%0.2%0.9%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

1 pkg affected
.NETServiceStack

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

ServiceStack ServiceStack Framework 4.5.14 is affected by: Cross Site Scripting (XSS). The impact is: JavaScrpit is reflected in the server response, hence executed by the browser. The component is: the query used in the GET request is prone. The attack vector is: Since there is no server-side validation and If Browser encoding is bypassed, the victim is affected when opening a crafted URL. The fixed version is: 5.2.0.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetServiceStack≥ 4.5.14&&< 5.2.05.2.0dotnet add package ServiceStack --version 5.2.0

Affected Products

1 product · 1 configurations
Application
servicestackservicestack
1 version
4.5.14

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update ServiceStack to 5.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-1010199 is resolved across your whole dependency graph.

  3. Workarounds

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

ServiceStack ServiceStack Framework 4.5.14 is affected by: Cross Site Scripting (XSS). The impact is: JavaScrpit is reflected in the server response, hence executed by the browser. The component is: the query used in the GET request is prone. The attack vector is: Since there is no server-side validation and If Browser encoding is bypassed, the victim is affected when opening a crafted URL. The fixed version is: 5.2.0.
O3 Security · Impact-Aware SCA

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CVE-2019-1010199: ServiceStack XSS — Fixed in 5.2.0