CVE-2026-49478

Fulcio has OIDC Discovery Redirect Following Allows SSRF and JWKS Substitution for Meta-Issuer Paths, with Kubernetes Service-Account Token Leakage

Published: Aug 13, 2026Updated: Sep 9, 2026 Sources: CVE List NVDCWE-918

8.7HIGH

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:HAttack Complexity

High

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:CScope

Changed

Impact

C:HConfidentiality

High

I:HIntegrity

High

A:NAvailability

None

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Weaknesses

CWE-918

Affected Products

sigstore

oss-projectaka gitsign, rekor, cosign

fulcioOn-prem

Security Products / pki-crypto

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Command and Control

Initial Access

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References

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

and 1 more references View all →

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