A flaw was found in Fulcio's OpenID Connect (OIDC) Discovery client. This vulnerability allows a remote attacker to perform Server-Side Request Forgery (SSRF) by redirecting discovery requests to internal systems. Additionally, an attacker can manipulate the JSON Web Key Set (JWKS) Uniform Resource Identifier (URI) to poison the verifier cache with malicious keys, enabling the validation of attacker-controlled signatures. Furthermore, the flaw can lead to the leakage of Kubernetes ServiceAccount tokens to third-party hosts through cross-host redirects or misconfigured MetaIssuers, potentially exposing sensitive cluster credentials.
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Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-f5mr-q85p-6hh6 | Fulcio has OIDC Discovery Redirect Following Allows SSRF and JWKS Substitution for Meta-Issuer Paths, with Kubernetes Service-Account Token Leakage |
Fixes
Solution
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Workaround
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References
History
Wed, 15 Jul 2026 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | A flaw was found in Fulcio's OpenID Connect (OIDC) Discovery client. This vulnerability allows a remote attacker to perform Server-Side Request Forgery (SSRF) by redirecting discovery requests to internal systems. Additionally, an attacker can manipulate the JSON Web Key Set (JWKS) Uniform Resource Identifier (URI) to poison the verifier cache with malicious keys, enabling the validation of attacker-controlled signatures. Furthermore, the flaw can lead to the leakage of Kubernetes ServiceAccount tokens to third-party hosts through cross-host redirects or misconfigured MetaIssuers, potentially exposing sensitive cluster credentials. | |
| Title | github.com/sigstore/fulcio: Fulcio: Server-Side Request Forgery and Kubernetes ServiceAccount token leakage | |
| Weaknesses | CWE-918 | |
| References |
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| Metrics |
threat_severity
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cvssV3_1
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Projects
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OpenCVE Enrichment
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Weaknesses
Github GHSA