CVE-2026-49478
Fulcio has OIDC Discovery Redirect Following Allows SSRF and JWKS Substitution for Meta-Issuer Paths, with Kubernetes Service-Account Token Leakage
CVSS Score
8.7
EPSS Score
0.0%
EPSS Percentile
0th
Fulcio is a certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Versions through 1.8.5 improperly follow cross-host redirects and attach Kubernetes ServiceAccount tokens during OIDC discovery, allowing a malicious or compromised issuer to perform blind SSRF, substitute and cache malicious JWKS keys, or disclose ServiceAccount tokens to external hosts. Version 1.8.6 blocks cross-host redirects, restricts token injection, and restricts local token loading. No known workarounds are available.
| CWE | CWE-918 |
| Vendor | sigstore |
| Product | fulcio |
| Published | Aug 13, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
sigstore / fulcio
< 1.8.6
References
github.com: https://github.com/sigstore/fulcio/security/advisories/GHSA-f5mr-q85p-6hh6 github.com: https://github.com/sigstore/fulcio/pull/2354 github.com: https://github.com/sigstore/fulcio/commit/378c654f48c3bafdced04ead7010aab2cb4c6ca1 github.com: https://github.com/sigstore/fulcio/releases/tag/v1.8.6