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.
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
Metrics threat_severity

None

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N'}

threat_severity

Moderate


cve-icon MITRE

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cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

Severity : Moderate

Publid Date: 2026-06-30T18:40:39Z

Links: CVE-2026-49478 - Bugzilla

cve-icon OpenCVE Enrichment

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