CVE-2026-49478
HighCVSS 8.7Exploitation Probability (EPSS)
Low risk20th percentile - higher than 20% of all known CVEs
Summary
Fulcio, a certificate authority for issuing code signing certificates for OIDC identities, 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.
Risk Assessment
Risk of ServiceAccount token disclosure, SSRF attacks, and JWKS key substitution, potentially leading to system integrity breaches and unauthorized access.
Recommendation
Update Fulcio to version 1.8.6 or later, which blocks cross-host redirects, restricts token injection, and restricts local token loading.
Other vulnerabilities in Fulcio
See all- CVE-2026-22772Medium
Prior to 1.8.5, Fulcio's metaRegex() function uses an unanchored regex, allowing attackers to bypass MetaIssuer URL validation and trigger SSRF to arbitrary internal services. The SSRF can only trigger GET requests, cannot mutate state, and the response is not returned, so only blind SSRF is possible.
- CVE-2025-66506High
Fulcio prior to 1.8.3 contains a vulnerability in the identity.extractIssuerURL function, which splits its untrusted argument on periods. A malicious request with an invalid OIDC identity token containing many period characters causes allocations of O(n) bytes, where n is the argument length, with a constant factor of about 16.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS