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Fencer Intel
high 8.2

CVE-2026-50194 json

Steeltoe vulnerable to management-port isolation bypass via spoofed Host header

published 4mo ago modified 4mo ago also GHSA-58f6-6rj2-3v8r , EUVD-2026-37801

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. When Steeltoe management endpoints versions 3.2.2 through 3.3.0 and 4.1.0 are configured to listen on an alternate port (`Management:Endpoints:Port` is configured), the middleware responsible for restricting access to the endpoints uses the `Host` HTTP header rather than the actual network socket port. Versions 3.4.0 and 4.2.0 patch the issue. If an immediate upgrade to a patched version is not possible, add explicit ASP.NET Core authorization (`RequireAuthorization`) to all sensitive actuator endpoints as a defense-in-depth measure independent of port isolation and/or configure the reverse proxy or load balancer to enforce the `Host` header value and prevent clients from setting an arbitrary port.

Patch / fix

  • nuget Steeltoe.Management.Endpoint 4.2.0
  • nuget Steeltoe.Management.EndpointCore 3.4.0

Is CVE-2026-50194 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
GitHub 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
nuget Steeltoe.Management.Endpoint
<4.2.0
4.2.0
nuget Steeltoe.Management.EndpointCore
>=3.2.2, <3.4.0
3.4.0

Affected products

  • SteeltoeOSS Steeltoe.Management.Endpoint
  • SteeltoeOSS Steeltoe.Management.EndpointCore

Classification

Weakness
  • CWE-288 Authentication Bypass Using an Alternate Path or Channel
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.