Allow directly-configured Kubernetes issuers to use in-cluster auth path#2356
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Gate the in-cluster CA + bearer-token attachment in httpClientForIssuer on the issuer being directly listed in OIDCIssuers, in addition to the existing match against k8sIssuerURL. Clusters whose --service-account-issuer is not literally https://kubernetes.default.svc (e.g. K3s, which uses https://kubernetes.default.svc.cluster.local) can again use the in-cluster auth path when their issuer URL is explicitly listed in OIDCIssuers. The SSRF/token-leak protection from sigstore#2354 is preserved: MetaIssuer wildcard matches against attacker-controlled hosts still do not receive the bearer token, because the new gate trusts only directly-listed OIDCIssuers entries (and the default k8sIssuerURL itself). Fixes sigstore#2355. Signed-off-by: Kevin Monroe <kevin.monroe@chainguard.dev>
Hayden-IO
approved these changes
May 29, 2026
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Thanks! I'll cut a new release shortly. |
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #2356 +/- ##
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- Coverage 57.93% 45.24% -12.70%
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Files 50 72 +22
Lines 3119 4721 +1602
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+ Hits 1807 2136 +329
- Misses 1154 2345 +1191
- Partials 158 240 +82 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Summary
Restore the in-cluster CA + projected service-account bearer-token auth path for directly configured Kubernetes issuers whose issuer URL is not literally
https://kubernetes.default.svc, while preserving the v1.8.6 SSRF / token-leak protections added in 378c654.This fixes the regression reported in #2355 for deployments such as K3s, where the service-account issuer may be
https://kubernetes.default.svc.cluster.localand is explicitly listed in OIDCIssuers.The existing
TestGetVerifier_MetaIssuerK8sTokenNotLeakedcontinues to pass, and a newTestGetVerifier_DirectConfiguredK8sIssuerGetsTokencovers the K3s case.Closes #2355
Release Note
https://kubernetes.default.svc.cluster.local) no longer received the in-cluster CA and service-account bearer token during OIDC discovery.Documentation
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