Kerberos Hub private key (X-Kerberos-Hub-PrivateKey) leaked to cross-host redirect target due to redirect-following HTTP client without CheckRedirect

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-50192: 0.42% estimated exploitation activity in the next 30 days; percentile 36.53 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The Kerberos Hub upload path sends the agent's Hub credentials in the custom X-Kerberos-Hub-PrivateKey and X-Kerberos-Hub-PublicKey request headers to the operator-configured Hub URL (config.HubURI). The HTTP client used (&http.Client{} in UploadKerberosHub) is constructed without a CheckRedirect policy, so it follows HTTP redirects automatically. Go's net/http strips only sensitive headers (Authorization, Cookie, WWW-Authenticate) on a cross-host redirect; it does not strip custom headers such as X-Kerberos-Hub-PrivateKey. As a result, if the configured HubURI returns a cross-host 30x redirect, the Hub private key is forwarded verbatim to the redirect target, disclosing the credential to an unintended third party (CWE-200 / CWE-522). Impact The Kerberos Hub private key (a long-lived secret authenticating the agent to Kerberos Hub) is leaked to an attacker-controlled host whenever the configured HubURI issues a cross-origin redirect. HubURI is operator configuration…

Published by the source

2 Jul 2026, 17:33 UTC

Last modified by the source

2 Jul 2026, 17:33 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-h5gx-45rj-2h5j

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# Patch Next advisory brief: CVE-2026-50192

Advisory: Kerberos Hub private key (X-Kerberos-Hub-PrivateKey) leaked to cross-host redirect target due to redirect-following HTTP client without CheckRedirect
IDs: CVE-2026-50192, GHSA-h5gx-45rj-2h5j
Record: https://patchnext.com/advisories/cve-2026-50192 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/kerberos-io/agent/machinery 0.0.0-20260528173546-51f1a52e170f. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/kerberos-io/agent/machinery: affected < 0.0.0-20260528173546-51f1a52e170f; fixed in 0.0.0-20260528173546-51f1a52e170f

## Suggested inspection (read-only)
- Go github.com/kerberos-io/agent/machinery: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/kerberos-io/agent/machinery.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-h5gx-45rj-2h5j (GitHub-reviewed advisory GHSA-h5gx-45rj-2h5j lists affected ranges: Go github.com/kerberos-io/agent/machinery >=0 <0.0.0-20260528173546-51f1a52e170f)

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